This wild, wacky weather pattern we've been in for the last couple of weeks has been tough to complain about, especially with below normal temperatures and abundant rain. Another good soaking occurred yesterday and overnight along a frontal boundary, and a few showers will still remain possible through 9:00 a.m. Several clouds will likely persist through late this morning, but these should break up this afternoon and a mixture of sunshine and cumulus. I think we'll have a chance to dry out some this afternoon as the aforementioned boundary will be located to our south. Highs should top out near 87 this afternoon. Clouds will be on the increase again early tomorrow morning in advance of another upper level disturbance, but temperatures should be able to drop to near 70.
Rain chances return again tomorrow afternoon with highs in the upper 80s. The best chance of rain will be on Sunday morning with highs topping out in the mid to upper 80s. Next week appears warmer and drier, but any excessive heat will be tempered by the amount of rain we've received lately.
Friday, July 31, 2009
Thursday, July 30, 2009
Severe Thunderstorm Watch Issued
The SPC has issued a severe thunderstorm watch for Oktibbeha County until 9 p.m. A line of strong to severe thunderstorms currently extends from Tallahatchie County to Rankin County. This line is moving to the northeast between 45 and 50 mph and should impact Starkville between 5:30 and 6:00 p.m. Expect some gusty winds, frequent lightning, and heavy rain as these storms move through the area.
Wednesday, July 29, 2009
Scattered PM Storms, Storms Overnight
A good soaking rain fell across all areas of the county yesterday and last night and kept temperatures well below normal. It doesn't appear that a soaking rain is in store for us today, but a few scattered showers and thunderstorms can't be ruled out this afternoon. It also appears that the sun will make a more significant appearance today, and this should allow temperatures to top out near 86. It's possible the high could be a couple of degrees warmer if we manage to stay dry through late this afternoon. By this evening, another upper level disturbance will begin to approach the region and should ignite a convective complex across Arkansas. The heaviest rain associated with the slow moving complex should remain to our west through sunrise tomorrow, but a better chance for showers and thunderstorms will exist after midnight. Lows tomorrow morning should drop to near 71.
Tuesday, July 28, 2009
Soggy, Cool
If you didn't receive much rain yesterday no need to worry because we'll make up for it today. The rain is getting an early start as a few showers this morning will make for a wet commute to work or school. We'll likely see periods of showers and possibly a few thunderstorms throughout the day as a very slow moving complex moves eastward out of Arkansas and Louisiana. Due to the slow movement of this complex, we could stand to see some impressive rainfall totals, and in fact, most areas will likely see over an inch of rain today. We won't see any sunshine today and with showers around for most of the day, highs will be well below normal as we should top out near 78 this afternoon. Rain will continue through the evening and become lighter in nature overnight. Temperatures should drop a few degrees to 72 tomorrow morning.
Monday, July 27, 2009
Isolated Showers, Warm
It's a muggy start to the day as temperatures are running near 70. At the surface, a cold front is situated across Arkansas and Northwest Tennessee but will find any southward push hard to come by today as its orientation to the upper air flow becomes more parallel. Still, this may provide just enough lift with the soupy air mass to spark a few isolated thundershowers this afternoon. Despite a mix of sun and clouds, we should be able to top out near 91 this afternoon. It appears that better chances for rain will occur overnight as an upper level disturbance approaches the area. In fact, a convective complex appears likely to form across Louisiana and Arkansas tonight, but the brunt of this should miss us. Still, a few scattered showers and thunderstorms will be possible after 2 a.m. Extensive cloud cover, showers, and southerly winds will make for another muggy morning with lows near 72.
Friday, July 24, 2009
Warming Up
It's a very pleasant start to the morning as temperatures dropped into the lower 60s under clear skies and light winds. We'll see a large rebound in temperatures this afternoon as the upper air trough that dominated our weather for the last several days lifts northward. At the same time, an upper level ridge will ever so slightly impinge on the area, and this will allow the thermometer to creep upwards. There may be a few patchy cumulus clouds throughout the day, but temperatures should manage to top out near 91 this afternoon. Skies will be clear for most of the night, but a few stray clouds may wander into the area just before sunrise. We should still be able to drop to 65 by tomorrow morning.
Saturday should be nice with a few clouds and afternoon highs in the low to mid 90s. As a cold front approaches on Sunday, look for increased cloud cover, a chance of afternoon and evening thunderstorms, and highs near 90.
Saturday should be nice with a few clouds and afternoon highs in the low to mid 90s. As a cold front approaches on Sunday, look for increased cloud cover, a chance of afternoon and evening thunderstorms, and highs near 90.
Thursday, July 23, 2009
Partly Cloudy, Warm
Cooler and drier air settled into the area in the wake of yesterday's frontal passage, but patchy areas of fog and a few clouds have kept temperatures in the mid 60s this morning. The fog should rapidly dissipate within the next hour, but we may still see a few mid and high level clouds throughout the morning followed by afternoon cumulus. The surface and upper air flow will be predominantly northwest today due to high pressure in Arkansas and a trough anchored over the Great Lakes, respectively. These two features will keep temperatures below normal and dew points comfortably in the 60s. Look for highs to top out near 86 this afternoon. Clouds should dissipate shortly after sunset, and with dry air and light winds, temperatures should be able to drop near 63 tomorrow morning. We'll warm temperatures back near normal for the next few days before a series of cold fronts affects the weather by late in the weekend and early next week.
Wednesday, July 22, 2009
Mostly Cloudy, Comfortable
Although most places around the county would consider yesterday's rainfall totals to be a disappointment, some places in the eastern part of the county received some decent rain. A second round of showers that formed earlier this morning along a cold front was responsible for this but is moving off to the east as we begin to dry out. The cold front will provide a reinforcing shot of drier air that will mainly be felt this evening. In the meantime, the forecast challenge today will be forecasting the dissipation of the stratus deck. Soundings suggest that these clouds will likely hold tough for much of the morning hours before breaking up early this afternoon. With this in mind, I'll forecast an afternoon high of 84. If the low clouds don't break up at all, we may only manage to reach the lower 80s, but if the clouds break up earlier than expected, we will be a few degrees warmer. It appears that skies become clear overnight, but a few areas of patchy fog could develop near sunrise. Still, with drier air in place, temperatures should be able to drop to 64.
Tuesday, July 21, 2009
PM Rain, Mild
More extensive cloud cover than I anticipated kept temperatures in the upper 60s to near 70 overnight. These clouds will hang tough today, but we should get a few peeks of sun throughout the morning before high level clouds arrive from the west late this morning and early afternoon. A few showers are ongoing across Northeast Mississippi, but these should move into Alabama and Tennessee shortly. A more impressive complex of showers and thunderstorms associated with a well-defined mesoscale convective vortex is moving across Western Arkansas. This complex should weaken some this morning as it encounters less unstable air to the east but may re-intensify this afternoon as instability increases. This complex may affect us later this evening, but we still stand a decent shot at seeing some scattered thunderstorms develop this afternoon. Cloud cover and possible showers will keep temperatures below normal again this afternoon with highs topping out around 85. We still won't be out of the woods tonight as additional showers may develop after midnight. Temperatures will be muggy again tomorrow morning as low only drop to near 69.
Monday, July 20, 2009
Afternoon Clouds, Warming
Three straight mornings of fall-like temperatures has really made a lot of people wish for fall. Unfortunately, this kind of weather won't consistently be felt for at least two months, but it was a refreshing change of pace to the heat and humidity. Columbus completed the hat trick by setting another recording this morning (58) and Golden Triangle tied its record (61). The unseasonably deep trough that has been in place for the last couple of days will begin to lift out this afternoon. However, we'll be able to sneak out another day with below normal temperatures as highs top out near 88 this afternoon. We'll likely see afternoon cumulus clouds along with a few higher clouds from convective complexes to our northwest throughout the day. Only one model forecasts any cloud cover overnight, but satellite imagery from upstream makes me have a tough time believing this scenario, especially with a shortwave moving through the upper flow. I expect more cloud cover overnight will keep prevent record-breaking temperatures again tomorrow morning, but it will still feel comfortable with lows near 64.
Three beautiful sunsets occurred over weekend, but the best was Friday evening as a few high clouds were moving through at sunset.
Three beautiful sunsets occurred over weekend, but the best was Friday evening as a few high clouds were moving through at sunset.
Saturday, July 18, 2009
Body Blows to El Nino
A weak El Nino persists across the equatorial Eastern Pacific, but recent atmospheric processes have halted the expanse of warm sea surface temperature anomalies. 1 C anomalies now only exist along and south of the equator between 155 W and 103 W with a localized pocket of slightly higher anomalies (~1.5 C) between 130 W and 110 W. The 29 C isotherm that was located as far east as 165 W a couple of weeks ago has retreated to 175 W owing to anomalously strong trade winds just south of the equator. Furthermore, the very warm anomalies (3-3.5 C) located 50 to 75 meters below the ocean surface between 130 W and 100 W that were observed last week have since shrunk and decreased to 2-2.5 C. Needless to say, the current El Nino has taken some major body blows the last few weeks.
Global wind signals continue to suggest the former La Nina may be delivering the body blows. Since frictional torque spiked last week, it has since decreased and leveled off near climatology as strong high pressure centers near 45 N and S observed in early July have weakened. Mountain torque remains about a half standard deviation below climatology with positive contributions coming from South America and the tropics and negative contributions coming from Eastern Asia and North America. Relative AAM continues to remain flat lined near one half standard deviation below climatology, and the recent fluctuations of relative AAM tendency have caused the GWO to oscillate between phases 1 and 3.
Recent responses to these phases have been for a large anticyclone to be centered over the Desert Southwest while a very deep trough has dominated the Eastern U.S. Much warmer than normal temperatures have been experienced across the West, and record low temperatures have been broken in the Southeast. I expect this pattern will continue for a couple of more days before the trough lifts out of the Southeast and into the Ohio Valley. This will allow temperatures to warm back to normal for most locations in the South, but northwesterly flow aloft will lead to the formation of mesoscale convective complexes this week which will penetrate into the Deep South. I think our area should see near normal temperatures and slightly above normal rainfall for the upcoming week. By next weekend and extending into week 2, an unseasonably strong Aleutian low will significantly amplify the ridge across the West. At the same time, another trough should re-establish itself into the eastern half of the country. It appears that the coolest air will miss us to the east, but cooler than normal temperatures will likely dominate the first half of week 2 along with above normal precipitation. The second half of week two should see the trough lift and the upper flow flatten, which should allow for temperatures to warm near normal. The bottom line is that the worst of the heat should remain to our west through week 2.
Monsoonal convection remains in place across the Asia subcontinent and other tropical convection is occurring in Indonesia and the Western Pacific. This continues to be good news for these areas that desperately need rain, but Tropical Storm Molave brought substantial rains and flooding to Hong Kong. Competing tropical convective signals continue to add some uncertainty to the future weather and climate link. The two areas of convection are in the Indian Ocean centered near 60 E and another centered near 165 E and will be battling for supremacy. I think the convection in the Indian Ocean should begin to fade in the next month, but the convection in the equatorial Western Pacific will likely only become stronger. At that point, I believe we should begin to see the ocean and atmosphere become more synced.
Global wind signals continue to suggest the former La Nina may be delivering the body blows. Since frictional torque spiked last week, it has since decreased and leveled off near climatology as strong high pressure centers near 45 N and S observed in early July have weakened. Mountain torque remains about a half standard deviation below climatology with positive contributions coming from South America and the tropics and negative contributions coming from Eastern Asia and North America. Relative AAM continues to remain flat lined near one half standard deviation below climatology, and the recent fluctuations of relative AAM tendency have caused the GWO to oscillate between phases 1 and 3.
Recent responses to these phases have been for a large anticyclone to be centered over the Desert Southwest while a very deep trough has dominated the Eastern U.S. Much warmer than normal temperatures have been experienced across the West, and record low temperatures have been broken in the Southeast. I expect this pattern will continue for a couple of more days before the trough lifts out of the Southeast and into the Ohio Valley. This will allow temperatures to warm back to normal for most locations in the South, but northwesterly flow aloft will lead to the formation of mesoscale convective complexes this week which will penetrate into the Deep South. I think our area should see near normal temperatures and slightly above normal rainfall for the upcoming week. By next weekend and extending into week 2, an unseasonably strong Aleutian low will significantly amplify the ridge across the West. At the same time, another trough should re-establish itself into the eastern half of the country. It appears that the coolest air will miss us to the east, but cooler than normal temperatures will likely dominate the first half of week 2 along with above normal precipitation. The second half of week two should see the trough lift and the upper flow flatten, which should allow for temperatures to warm near normal. The bottom line is that the worst of the heat should remain to our west through week 2.
Monsoonal convection remains in place across the Asia subcontinent and other tropical convection is occurring in Indonesia and the Western Pacific. This continues to be good news for these areas that desperately need rain, but Tropical Storm Molave brought substantial rains and flooding to Hong Kong. Competing tropical convective signals continue to add some uncertainty to the future weather and climate link. The two areas of convection are in the Indian Ocean centered near 60 E and another centered near 165 E and will be battling for supremacy. I think the convection in the Indian Ocean should begin to fade in the next month, but the convection in the equatorial Western Pacific will likely only become stronger. At that point, I believe we should begin to see the ocean and atmosphere become more synced.
Friday, July 17, 2009
Atlantic Tropical Outlook
Quiet weather continues in the tropical Atlantic basin as a strong TUTT dominates the Caribbean and Central Atlantic. That hasn't stopped the African wave train from rolling impressive waves off the coast of Africa, but they have been beaten by dry air and cool waters once they emerge into the Atlantic. Easterly winds remain strong across the Eastern Atlantic, but recent migration of subtropical ridge to the north and west has allowed for a relaxation of the easterlies. Normally, this would allow water temperatures to warm slightly, but an expansive area of Saharan dust will likely prevent full sunshine from warming temperatures in the main development region. If this dust continues, it will have a substantial impact on long-track Cape Verde systems in August and September.
The weather should be great today for most of the Caribbean islands, but a few showers and thunderstorms may affect the Lesser Antilles this evening as an easterly wave approaches. This tropical wave is centered near 14N and 54W and is quickly encountering a very hostile upper level environment. This wave should rapidly dissipate in the next 24-36 hours due to wind shear in excess of 30 knots and significant amounts of dry air and Saharan dust.
A second and healthier looking tropical wave is centered near 12N and 35W. A small area of thunderstorms is associated with the wave, but a QuikSCAT pass this morning did not indicate a closed circulation. Despite this, wind shear remains light and water temperatures are sufficient for some development as this wave moves to the west. However, dry air and Saharan dust remain to the west and north of this tropical wave so it's very possible it could be entrained into this wave. A few computer models indicate a lowering of pressure in the vicinity of the wave, but no model forecasts any development through this weekend. This seems reasonable given the dry air, marginal water temperatures, and a downward motion pulse. Still, this will need to be watched as it moves west and west northwest over the next several days. The subtropical high is forecast to shift westward early next week at the same time a trough split occurs in the Eastern U.S. With warmer water temperatures in place across the Western Atlantic, a more favorable environment for development will exist at that time.
Showers and thunderstorms are located in the tropical waters off the Gulf Coast and Carolinas, but development of these areas will become highly unlikely through this weekend as a trough deepens into the Southeast.
The weather should be great today for most of the Caribbean islands, but a few showers and thunderstorms may affect the Lesser Antilles this evening as an easterly wave approaches. This tropical wave is centered near 14N and 54W and is quickly encountering a very hostile upper level environment. This wave should rapidly dissipate in the next 24-36 hours due to wind shear in excess of 30 knots and significant amounts of dry air and Saharan dust.
A second and healthier looking tropical wave is centered near 12N and 35W. A small area of thunderstorms is associated with the wave, but a QuikSCAT pass this morning did not indicate a closed circulation. Despite this, wind shear remains light and water temperatures are sufficient for some development as this wave moves to the west. However, dry air and Saharan dust remain to the west and north of this tropical wave so it's very possible it could be entrained into this wave. A few computer models indicate a lowering of pressure in the vicinity of the wave, but no model forecasts any development through this weekend. This seems reasonable given the dry air, marginal water temperatures, and a downward motion pulse. Still, this will need to be watched as it moves west and west northwest over the next several days. The subtropical high is forecast to shift westward early next week at the same time a trough split occurs in the Eastern U.S. With warmer water temperatures in place across the Western Atlantic, a more favorable environment for development will exist at that time.
Showers and thunderstorms are located in the tropical waters off the Gulf Coast and Carolinas, but development of these areas will become highly unlikely through this weekend as a trough deepens into the Southeast.
A Few Clouds, Warm
Most everyone around the county received a good soaking rain yesterday morning and/or last night. In fact, some places in the southern part of the county received over 3" of rain yesterday! The cold front responsible for the rain is knocking on the doorstep of Northwest Mississippi. This front should push through our area early this afternoon as an upper air trough to our north deepens. Ahead of the front, we could see an isolated shower or two develop later this morning, but we should remain mostly dry.We should see a few clouds throughout the day with highs topping out near 90 this afternoon.
The true effects of the front will be felt beginning this evening as much drier air filters into the region. Dew points will drop into the 50s tonight, and with clear skies and light winds, I'll forecast a low of 60. The Raw GFS is forecasting 56, but with most areas receiving rain the last couple of days, I can't go that low. The weekend is shaping up to be absolutely perfect with highs in the mid 80s on Saturday and Sunday! Temperatures will slowly creep back into the 90s next week.
The true effects of the front will be felt beginning this evening as much drier air filters into the region. Dew points will drop into the 50s tonight, and with clear skies and light winds, I'll forecast a low of 60. The Raw GFS is forecasting 56, but with most areas receiving rain the last couple of days, I can't go that low. The weekend is shaping up to be absolutely perfect with highs in the mid 80s on Saturday and Sunday! Temperatures will slowly creep back into the 90s next week.
Thursday, July 16, 2009
Scattered Storms, Warm
It's a very muggy start to the morning with temperatures currently running in the mid to upper 70s. With the amount of difficult forecasts there have been recently, you would think this is the spring instead of summer. Today certainly qualifies as a tough forecast thanks to an ongoing convective complex across North Mississippi, Western Tennessee, and Northeast Arkansas. The current movement of this complex of storms should stay to our north, but any outflow boundary emanating from the storms could shoot our direction and increase the threat for storms later this morning and afternoon. Regardless of whether this happens, the atmosphere will be supportive of shower and thunderstorm development today due to a cold front that currently stretches from the Great Lakes to Texas. The front should advance as close as Northeast Arkansas and Western Tennessee by this evening, but the upper level flow will cause the front to stall in that general vicinity. This doesn't mean that today will be a washout, but there will be scattered showers and thunderstorms later this morning and afternoon. A few of these storms could be on the strong side, but weak wind shear will be the main inhibiting factor for severe thunderstorms.
The trickiest part of the forecast is the high temperature. Cloud cover associated with the convective complex to our north is expanding, but skies are mostly sunny around the area this morning. This is likely to last for a couple of hours before the high clouds associated with the storms to our north move into the area. I think we should be able to top out near 92, but if we stay sunny through most of the morning, we could be a couple of degrees warmer. A new complex of storms will develop tonight across Eastern Kansas and Western Missouri and will move southeast. The brunt of these storms should remain to our northwest through sunrise, but there will continue to be a chance of rain overnight. Any storms that form overnight could be strong given the enhanced wind shear, but forecast soundings show an inversion developing in the lower levels overnight which will likely prevent strong winds from reaching the surface. A threat of storms combined with cloud cover will make for another muggy night with lows dropping to 73 by the morning. The weekend continues to look pleasant with highs in the 80s.
The trickiest part of the forecast is the high temperature. Cloud cover associated with the convective complex to our north is expanding, but skies are mostly sunny around the area this morning. This is likely to last for a couple of hours before the high clouds associated with the storms to our north move into the area. I think we should be able to top out near 92, but if we stay sunny through most of the morning, we could be a couple of degrees warmer. A new complex of storms will develop tonight across Eastern Kansas and Western Missouri and will move southeast. The brunt of these storms should remain to our northwest through sunrise, but there will continue to be a chance of rain overnight. Any storms that form overnight could be strong given the enhanced wind shear, but forecast soundings show an inversion developing in the lower levels overnight which will likely prevent strong winds from reaching the surface. A threat of storms combined with cloud cover will make for another muggy night with lows dropping to 73 by the morning. The weekend continues to look pleasant with highs in the 80s.
Wednesday, July 15, 2009
Steamy
It's a pleasant but muggy start to the morning as temperatures have already warmed into the mid to upper 70s. A few clouds are evident on satellite this morning across Northeast Mississippi, but most areas should see a good supply of sunshine today with only afternoon cumulus expected to develop. One or two of these cumulus clouds could grow into a shower or thunderstorm, but any showers should remain very isolated given warming temperatures aloft. Temperatures will be on the warm side as low level temperatures support highs in the middle 90s. We should be able to top out around 96 today, but the temperature will feel like 105 at times this afternoon. Quiet weather is expected tonight with only a few patchy clouds. Temperatures will be muggy as we only drop to 74 by tomorrow morning. Excellent model and ensemble agreement continues to support the idea of much cooler weather this weekend with highs in the low to mid 80s and lows near 60!
Tuesday, July 14, 2009
Some Clouds, Seasonal Temperatures
Much of the county received some much needed rain yesterday with most amounts between a quarter and a half inch, but some communities in the western part of the county likely received higher amounts based on radar estimates. The weather is much quieter this morning in our area, but showers and thunderstorms are affecting portions of Western Mississippi. This complex of storms should stay to our west, but a few debris clouds have moved across this area this morning and caused temperatures to rise slightly.
The forecast today is quite tricky as it appears that another convective complex across Northwest Arkansas and Southwest Missouri will follow on the heels of the complex across Western Mississippi. If this holds true, we may see another round of clouds later this morning followed by cumulus clouds in the afternoon. Yesterday's thunderstorm complexes put enough of a dent in the upper level ridge that it has moved back to the west, hence why the storm track is off to our west. I think this will remain the case today, which means we should be dry. The dent in the ridge also means temperatures will be warmer than yesterday but still seasonable for this time of the year as we'll top out near 92 this afternoon. Dew points in the lower 70s will also make the temperature feel close to 100 at times later today. The weather will remain quiet overnight as the upper level ridge builds back into the area. A few clouds may arrive just before sunrise as temperatures will drop to near 74. Model guidance remains leaning toward the idea that tomorrow will be the hottest day of the year thus far with highs in the upper 90s. Not to be outdone, much cooler temperatures are on the way by the weekend and early next week as an anomalously deep upper air trough settles over the region.
The forecast today is quite tricky as it appears that another convective complex across Northwest Arkansas and Southwest Missouri will follow on the heels of the complex across Western Mississippi. If this holds true, we may see another round of clouds later this morning followed by cumulus clouds in the afternoon. Yesterday's thunderstorm complexes put enough of a dent in the upper level ridge that it has moved back to the west, hence why the storm track is off to our west. I think this will remain the case today, which means we should be dry. The dent in the ridge also means temperatures will be warmer than yesterday but still seasonable for this time of the year as we'll top out near 92 this afternoon. Dew points in the lower 70s will also make the temperature feel close to 100 at times later today. The weather will remain quiet overnight as the upper level ridge builds back into the area. A few clouds may arrive just before sunrise as temperatures will drop to near 74. Model guidance remains leaning toward the idea that tomorrow will be the hottest day of the year thus far with highs in the upper 90s. Not to be outdone, much cooler temperatures are on the way by the weekend and early next week as an anomalously deep upper air trough settles over the region.
Monday, July 13, 2009
Storms This Morning, Still Warm
Make no mistake, the sound you're hearing this morning is rain and thunder! Everyone in the county should get some rain today as a subtle upper level disturbance has produced a large complex of showers and thunderstorms across North Mississippi. This complex should move through by 10:30 this morning, but we'll turn our attention back to the northwest as another complex will be diving southeast out of Arkansas. The brunt of this complex will likely affect areas to our west, but the outer fringes could still give us some additional rain this afternoon. Most areas in the county will wind up with rainfall totals under a half inch today, but there may be a few isolated higher amounts up to 1". This rainfall will also be extremely beneficial in that it will help keep temperatures slightly in check today, tomorrow, and Wednesday. Highs today will still be rather warm despite the rain and clouds, but we should manage to top out around 93 this afternoon. The weather should be quiet tonight with only a few clouds overnight, but it will be very muggy with lows dropping to 74 tomorrow morning.
Saturday, July 11, 2009
La Nina Still Fighting
The big climate news this week was the official declaration from NOAA that El Nino has begun. SSTs in the equatorial Pacific Ocean remain slightly above normal (0.5-1 C) with the warmest anomalies along the equator between 150 W and 110 W. The 1 C anomaly has actually shrunk in size the last few weeks as the trade winds have remained slightly stronger than normal (0.5-1 m/s) just south of the equator between the Dateline and 100 W. However, subsurface (50-75 m) anomalies have actually increased to 3-4 C between 130 W and 100 W so any relaxation of the trades in this area will result in the anomalously warm water rising closer to the surface.
An analysis of the equatorial Pacific Ocean waters certainly confirms that a weak El Nino is ongoing, but the global wind and tropical convective signals suggest that La Nina is still valiantly fighting. Recent positive mountain torque has since dropped near climatology with very weak negative contributions coming from East Asia and North America. Frictional torque has increased the last few days, possibly due to anomalously strong westerly winds associated with low pressure centers between 40-45 S. Despite this, relative AAM remains near 1 standard deviation below climatology. Furthermore, the wind signals remain weakly projected in GWO phases 1-3, the La Nina attractor. The SOI has also generally remained positive since June 22 as stronger than normal high pressure has persisted near Tahiti, and in fact, the 30 day average is close to 4.
In addition to the wind signals, the tropical convective signals also favor a La Nina type pattern with strong convection moving out of the Indian Ocean and slowly into Indonesia. However, OLR anomalies suggest another area of convection centered near the Dateline, and this will need to be watched closely over the next couple of weeks for persistence and/or strengthening. If this area indeed persists and/or strengthens and the convection over Indonesia moves further east, the tropical convective signals will finally begin favoring an El Nino pattern.
The 250 mb streamfunction composites for GWO phases 1-2 seem to depict the current global circulation, especially the circulation across the United States. A strong upper anticyclone dominates the Southern Plains while a weak shortwave trough is located over the Pacific Northwest. This upper air pattern will quickly flatten out through the middle of next week before a strong shortwave trough digs into the Eastern U.S. by the end of the week. This will provide a chance of rain and slightly cooler temperatures to the Southeast and continued cool weather across the Great Lakes and Northeast. The upper level ridge will move westward and will bring heat back to the Western U.S.
With the weak GWO projection likely to continue, it won't be of much value in the medium and long range. However, keeping with the idea that the current global circulation pattern persists, the heat ridge will likely slide back to the east by Week 2. This means a return of the warmth to the Southern Plains and the Southeast. The main storm track will be across the northern part of the country where periodic episodes of severe weather will occur. Passing shortwaves should also prevent the Great Lakes and Northeast from seeing prolonged hot weather in the foreseeable future.
An analysis of the equatorial Pacific Ocean waters certainly confirms that a weak El Nino is ongoing, but the global wind and tropical convective signals suggest that La Nina is still valiantly fighting. Recent positive mountain torque has since dropped near climatology with very weak negative contributions coming from East Asia and North America. Frictional torque has increased the last few days, possibly due to anomalously strong westerly winds associated with low pressure centers between 40-45 S. Despite this, relative AAM remains near 1 standard deviation below climatology. Furthermore, the wind signals remain weakly projected in GWO phases 1-3, the La Nina attractor. The SOI has also generally remained positive since June 22 as stronger than normal high pressure has persisted near Tahiti, and in fact, the 30 day average is close to 4.
In addition to the wind signals, the tropical convective signals also favor a La Nina type pattern with strong convection moving out of the Indian Ocean and slowly into Indonesia. However, OLR anomalies suggest another area of convection centered near the Dateline, and this will need to be watched closely over the next couple of weeks for persistence and/or strengthening. If this area indeed persists and/or strengthens and the convection over Indonesia moves further east, the tropical convective signals will finally begin favoring an El Nino pattern.
The 250 mb streamfunction composites for GWO phases 1-2 seem to depict the current global circulation, especially the circulation across the United States. A strong upper anticyclone dominates the Southern Plains while a weak shortwave trough is located over the Pacific Northwest. This upper air pattern will quickly flatten out through the middle of next week before a strong shortwave trough digs into the Eastern U.S. by the end of the week. This will provide a chance of rain and slightly cooler temperatures to the Southeast and continued cool weather across the Great Lakes and Northeast. The upper level ridge will move westward and will bring heat back to the Western U.S.
With the weak GWO projection likely to continue, it won't be of much value in the medium and long range. However, keeping with the idea that the current global circulation pattern persists, the heat ridge will likely slide back to the east by Week 2. This means a return of the warmth to the Southern Plains and the Southeast. The main storm track will be across the northern part of the country where periodic episodes of severe weather will occur. Passing shortwaves should also prevent the Great Lakes and Northeast from seeing prolonged hot weather in the foreseeable future.
Friday, July 10, 2009
Dry, Warmth Continues
It certainly feels more muggy outside and rightfully so with dew points inching slowly back into the 70s this morning. As the day progresses, winds will veer to a southeastly component and will keep dew points much higher than the last several days. Satellite imagery shows a convective complex across Missouri is diving southeast. This complex should weaken with time as it encounters slightly more stable air to its south, but we could see a few of the cirrus clouds from this complex later this afternoon and evening. Speaking of clouds, it appears as though we'll continue to see a few patchy afternoon cumulus, but these should not have a major impact on temperatures. Although the upper level ridge expands eastward today, low level temperatures do not appear to warm much from yesterday so persistence seems to be the best way to go again. With that in mind, highs should top out near 94 again today, but the higher dew points will make it feel slightly warmer than that. A few clouds may pass by at times overnight with temperatures bottoming out near 72 tomorrow morning. I notice the newest model guidance has 100 for next Tuesday -- ouch! That's certainly believable with most communities around the area receiving less than 3" of rain in the last month.
Thursday, July 9, 2009
Atlantic Tropical Outlook
The tropical Atlantic basin continues to remain very quiet with only a few areas worth mentioning. A small tropical wave centered near 11 N 56 W will approach the southern Lesser Antilles tonight and tomorrow. A few showers and thunderstorms along with breezy winds will accompany this wave and impact Grenada, The Grenadines, St. Vincent, St. Lucia, and Barbados. Development of this system does not appear likely even though it is surrounded by light wind shear and water temperatures in the lower 80s. The main negative factor for short-term development will be its low latitude and possible impact with South America. Once it moves into the Caribbean, wind shear dramatically increases and will contribute to the wave's dissipation by the end of the weekend.
A second tropical wave emerged off the coast of Africa yesterday and is currently centered near 7 N and 24 W. Development of this wave seems highly unlikely given an unfavorable climatological period, strong wind shear, and a significant amount of Saharan dust in its path. The low latitude nature of these tropical waves can be attributed to the fact that the subtropical high in the Atlantic is suppressed further south than normal.
The main area of concern is an area of showers and thunderstorms off the coast of the Carolinas in association within a stalled frontal boundary. An upper air trough remains in proximity to the old frontal boundary and is contributing to very strong wind shear. Until this trough lifts out, which is not forecast to happen until this weekend, development is highly unlikely given the hostile environment. Even if development does occur with this system this weekend, it will not pose any threat to the U.S. mainland. The rain will be welcomed relief for many parched areas in North and South Carolina.
A second tropical wave emerged off the coast of Africa yesterday and is currently centered near 7 N and 24 W. Development of this wave seems highly unlikely given an unfavorable climatological period, strong wind shear, and a significant amount of Saharan dust in its path. The low latitude nature of these tropical waves can be attributed to the fact that the subtropical high in the Atlantic is suppressed further south than normal.
The main area of concern is an area of showers and thunderstorms off the coast of the Carolinas in association within a stalled frontal boundary. An upper air trough remains in proximity to the old frontal boundary and is contributing to very strong wind shear. Until this trough lifts out, which is not forecast to happen until this weekend, development is highly unlikely given the hostile environment. Even if development does occur with this system this weekend, it will not pose any threat to the U.S. mainland. The rain will be welcomed relief for many parched areas in North and South Carolina.
Less Clouds, More Heat
Temperatures this morning are rather pleasant as skies remained clear overnight. Temperatures will be anything but pleasant this afternoon as an upper level ridge begins to build across the region. This building ridge will also allow temperatures to warm just above the surface so the thermometer will slowly climb over the next few days. It doesn't appear that cloud cover will be able to help much today, but a few stray cirrus clouds may be visible later this morning and early afternoon. Highs this afternoon will top out around 94, but the good news is that we won't have to contend with the humidity for another day. Winds will turn back to the southeast tonight and moisture will gradually increase. Skies should be mostly clear, but lows will only bottom out near 69 tomorrow morning.
Tuesday, July 7, 2009
Partly Cloudy, Warm
We'll deal with clouds again today as a two strong upper air disturbances pass through the area today. I still think we'll remain dry as deeper moisture resides just to our south, but a rogue shower is not out of the question across North Mississippi today. Persistence is likely the best way to handle temperatures today even though they will be a degree or two warmer than yesterday. I think we'll top out around 91 this afternoon. It appears as though as clouds will pass by at times overnight so we should only drop to 69 tomorrow morning. The forecast for the heat still looks good for this weekend and especially next week. With very little rain recently, highs next week may be the hottest of the year.
Some Clouds, Warm
Cloud cover kept us a little warmer than I expected as temperatures only dropped to 70 this morning. We'll continue to see a mixture of clouds and sun for the majority of the day, and this will once again keep temperatures in check despite warming temperatures aloft. We should be able to top out near 90 this afternoon. Rain chances are zero today as we remain on the "cooler" side of a frontal boundary located across Southern Mississippi. Low stratus clouds will continue to blanket the area tonight, and I think this will only allow temperatures to drop to 68 tomorrow morning.
Monday, July 6, 2009
Morning Showers, Slightly Cooler
Some much needed rain found just about every way imaginable to miss us yesterday and so far this morning. Those of you living in western part of the county may disagree as some heavier rain is moving through at this time. However, it will exit the area shortly and will end our chances for any appreciable rain as a cold front has pushed to our south. A few showers may be possible this morning, but drier air will filter into the area this afternoon and effectively limit any chance for rain. The silver lining to that is that temperatures will be below normal again today with an afternoon high of 87. Helping to hold temperatures down today will also be the presence of cloud cover and this will linger into tonight. It will have the opposite effect tonight as it will hold temperatures up despite the drier air. Still, we should be able to drop to near 68 tomorrow morning. Hot and dry weather will return again this week as a strong ridge takes shape, but at this time, it appears that the center of the heat bubble will remain just to our west.
Wednesday, July 1, 2009
Another Hot One
A few clouds associated with an upper level disturbance kept temperatures in the 70s overnight. These clouds are quickly pushing off to the south so today should feature mostly sunny skies. This should allow highs this afternoon to top out near 94. Temperatures will actually be a little cooler overnight since skies will be clear and dew points will be in the mid 60s. In fact, we should drop to near 66 tomorrow morning.
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