Archive for January, 2010

Dry Thru Wednesday….Severe Storms Coming?

Today was a beautiful day across Alabama with temperatures topping out in the 60′s across most locations and sunny skies.  Tonight….some patchy fog is developing especially along river banks and nearby waterways.  Some lower clouds across the Tennessee Valley will roll through as a mid level disturbance moves north of the area, but the clouds should be long gone by mid morning.  This will set the stage for another beautiful, warm day across the state with 60′s common area wide with some middle 60′s being likely. 

As we head into Wednesday…..moisture advection will begin ahead of our next storm system.  Clouds will likely increase during the mid morning hours and spread across the entire state through the day.  Rain will increase from west to east Wednesday night.  Rainfall totals could be on the order of a couple of inches and some localized flooding may become an issue due to recent rains.  The main threats become evident by mid morning on Thursday, however.

Transitioning to the potential for severe weather now……Thursday could certainly be an active day in that department if our latest mesocale model (the NAM) is correct.  There are indications that morning rainfall will move out of the area as our dynamic system aloft rolls across.  Pictured below is our potential energy for noon on Thursday.

On the graphic above, our low level shear (strength of low level winds turning) is decreasing but the CAPE (potential energy available) is breaching 1000-1500 j/kg.  This is rather significant for a thunderstorm event in the winter.  Storms in the winter normally dont have the energy to withstand the strong winds….however, this may be a different animal.  Now….here is the upper level system aloft..

This image shows height falls aloft with a potent mid level low over West Tennessee at noon on Thursday.  This is bringing cooler air aloft with it and making our air very unstable by noon.  These type of setups normally bring severe weather to the area….some of which has been significant.  Now….one final graphic to put all of this together….a sounding for Central Alabama on noon Thursday. 

This sounding indicates a few things that are alarming to me….first is the temperature drop as you rise above the surface…otherwise called a lapse rate.  The lapse rate in the lower levels is very steep.  The temperature falls very fast as you rise above the surface…which allows for thunderstorm updrafts to accelerate at high rates of speed in an upward motion.  The second thing is the mid level dry air. (Where the green line moves sharply left).  This leads me to believe that anything that forms will be out by itself or cellular on Thursday afternoon.  The final thing the wind fields.  The winds are pretty unidirectional (blowing in close to the same direction).  Directional shear isn’t extremely impressive, but the change in speed with height could still yield the potential for a couple of tornadoes in any super cells that are able to develop. 

There are two negatives that I see that could have implications on the impact of this event.  One….the atmosphere could become overworked with the morning convection.  The storms during the overnight could take a toll on the environment that the upper level system will have to work with in other words.  Or….once the morning rain leaves….do we have anything to produce lift?  We may not have enough surface “convergence” to allow storms to develop since our winds turn southwesterly.  These are all questions that will be ironed out over the next couple of days, but I can say this…..I would bet on having some large hail on Thursday across portions of the area at the very least.  We will be changing our chase status to moderate for Thursday. 

We will get into the Saturday night and Sunday event after this one passes….and yes severe weather will be possible then as well.  Stay tuned…

Severe Weather Around the Corner?

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As we have illuded to the last couple of days, it looks as if we are about to enter an active weather pattern with a couple of severe weather threats looming. The first around Wednesday/Thursday across the Gulf Coastal areas….then again over the weekend over a potentially larger chunk of real estate as the Storm Prediction Center day 4-8 outlook indicates. Later this evening we will go more in depth with the upcoming weather situation and give you our forecast thoughts. Stay Tuned…

Surface Low Moving Through Mississippi

Our surface low is on the move this evening….moving northward across sections of eastern Mississippi where pressure’s around 1003-1004mb have been realized.  The surface system will continue its northward track with the slug of moisture present on the east side of the system.  We will keep rain in the forecast throughout the night and early in the morning.  It looks as if temperatures will remain steady through the night as well. 

The rain will begin to move out of most of the state by mid morning but the clouds will hang tough through the day.  Sunny skies will arrive once again on Monday with high temperatures cracking the low-mid 60′s.  Low temperatures should bottom out in the upper 30′s/lower 40′s.

The weather won’t remain quiet for too long, however, with a strong subtropical jet coming on shore along the southern California coastline.  It looks as if this strong upper level jet could have implications on our weather further into the work week with more rain and possibly some active thunderstorms.  Stay tuned…..the weather looks to keep changing over the coming few weeks. 

Rain Progressing Northward

On the radar scope this morning…..a surface trof (area of convergence that allows air to rise and form rain) is located over southern and eastern sections of the area ahead of a surface low pressure system a couple hundred miles from the Gulf Coast.  This trof is aiding in the area of rainfall that is spreading northward from Eufaula – Greenville – Demopolis.  The rain will continue to increase and grow more widespread later this afternoon as previously expected with some heavy rain possible later this afternoon into tonight as the surface system draws closer.

…FLASH FLOOD WATCH IN EFFECT FROM SATURDAY MORNING THROUGH
SATURDAY EVENING…

THE NATIONAL WEATHER SERVICE IN TALLAHASSEE HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF SOUTHEAST ALABAMA…FLORIDA
AND GEORGIA…INCLUDING THE FOLLOWING AREAS…IN SOUTHEAST
ALABAMA…COFFEE…DALE…GENEVA…HENRY AND HOUSTON. IN
FLORIDA…BAY…CALHOUN…COASTAL WALTON…DIXIE…FRANKLIN…
GADSDEN…GULF…HOLMES…INLAND WALTON…JACKSON…
JEFFERSON…LAFAYETTE…LEON…LIBERTY…MADISON…TAYLOR…
WAKULLA AND WASHINGTON. IN GEORGIA…BAKER…BEN HILL…
BERRIEN…BROOKS…CALHOUN…CLAY…COLQUITT…COOK…
DECATUR…DOUGHERTY…EARLY…GRADY…IRWIN…LANIER…LEE…
LOWNDES…MILLER…MITCHELL…QUITMAN…RANDOLPH…SEMINOLE…
TERRELL…THOMAS…TIFT…TURNER AND WORTH.

* FROM SATURDAY MORNING THROUGH SATURDAY EVENING

* WIDESPREAD RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE EXPECTED FROM
EARLY SATURDAY MORNING THROUGH SATURDAY EVENING. LOCALLY HIGHER
AMOUNTS ARE POSSIBLE. DEPENDING ON WHERE AND HOW QUICKLY THIS
RAIN FALLS…FLOODING COULD DEVELOP IN LOW-LYING AND POOR
DRAINAGE AREAS.

* THE MOST LIKELY AREAS TO BE IMPACTED ARE URBAN AREAS…ALONG SMALL
CREEKS AND LARGE DITCHES…AND LOW-LYING ROADS.

Rain Moving In

Rain is progressing northward this evening along the Gulf coast.  Places like Pensacola and Crestview, Florida are experiencing moderate rain at this hour.  The moisture is currently south of I-85, but it’s progressing northward slowly but steadily.  There could be some shower activity closer to central Alabama by mid morning Saturday. 

As you can see on our graphic above, the heaviest rainfall is expected to remain south of I-20 and east of I-65 for the most part.  Our 1-2″ forecast should verify nicely across the southern half of the state.  We will continue to keep thunder out of the equation since unstable air will remain well south of the region. 

A Flash Flood Watch is in effect for the Mobile and Dothan areas throughout the weekend.  Saturated soils could lead to some localized flooding where heavier amounts of rainfall occur.  Stay tuned…

Red Flag Warning: North of I-20

Burning is prohibited this afternoon until 5PM as a Red flag warning is in effect for the northern 1/3 of Alabama.  This is due to low relative humidity values across the area and some light winds.  This advisory shouldn’t be carried over into tomorrow due to increasing moisture and rainfall becoming more likely.  Stay tuned…

Great Weather Today

Starting out this morning with a look at Childersburg as of 9:05AM.  Blue skies continue to be widespread across the area and this is the case for most camera locations that we are viewing this morning.  Today….we should top out in the upper 50′s with some areas reaching the low 60′s.  Rain will not come into the picture until tomorrow as our big storm system to the southwest is slow or organize.

This morning….rain is spreading northward along the east Texas Coast as low pressure continues to organize in the western Gulf of Mexico.  Showers and thunderstorms have been common from the Houston/Galveston areas and southward.  The system is expected to pick up some speed as we head into tonight and push out over the central gulf spreading rain along the coastline of Louisiana, Mississippi, Alabama, and Florida on Saturday.  I expect most of our rainfall to come after the 3PM hour tomorrow….along the I-20 cooridor, but some places to the south could begin to see the rain showers a little before noon. 

There is some conflicting guidance in terms of how much rainfall we actually receive, but we will stick with our 1-2″ forecast for now,  This may need to be shifted toward the south later….as some models suggest that the bulk of the rain will move through southeast Alabama in the Dothan vicinity.  Temperatures will hang in the lower 50′s on tomorrow with the clouds and rain becoming more widespread.  Some windy conditions could also occur….but should remain below wind advisory criteria. 

We will update you later in the evening on the progression of the system and if we foresee any changes to the forecast.  At this point, the weekend still looks to be rather wet.  Have a great, T.G.I.F.!

Evening Update…..Next Weather Maker Developing

As you can see above…..our next weather maker is developing across the southern tip of Texas with showers and thunderstorms developing eastward into the Gulf of Mexico.  This surface low will continue to track eastward and get it’s act together over the next day as rainfall continues to spread north and eastward.  The upper air system continues to intensify and we will need to be weary of it.  There is very little upper air data that comes out of the Gulf of Mexico (besides a few planes) so the forecast guidance could take an unexpected turn at any moment. 

Currently…..it seems as if rainfall will begin moving into southern sections of Alabama tomorrow evening as we begin to moisten up the lower levels.  The main rain event will hold off until the day on Saturday as the surface low tracks closer toward the coast and then onshore across southeast Alabama.  Everything still suggests 1-2″ rainfall totals along the I-20 cooridor with higher amounts to the south.  No severe weather is expected.

In the extended…..it looks as if we will remain warm through much of next week with maybe a couple of shots at some active thunderstorms toward next weekend.  Guidance continues to indicate a very strong jet stream carving out a trough of low pressure along Pacific coast.  A surface low will likely develop east of the Rockies and give us a warm sector scenario.  It’s way too early to look at any specifics as far as severe weather is concerned…..but keep in mind that we could have a little more “interesting” weather than as of late.

Toward the end of the month…..I believe we head back into the deep freeze again!  We will watch for a “Greenland” blocking scenario and an Alaskan ridge to give us the deep troughing it takes to get arctic air here.  This allows the cold air to dump southward from the frozen tundra of the north pole.  This looks possible once again as we head toward the beginning of February.  Never dull in the south!

Warmer Today….Rainy Weekend Ahead

Low pressure is already beginning to develop and move across Texas towards the Gulf of Mexico this morning where pressure falls are occurring due to the progression of a strong upper level trough.  Rainfall is already beginning to develop along the Texas coast where the this pressure drop is beginning…..and should spread across much of the northwestern Gulf through today into tomorrow.  This will turn the surface flow toward the southeast and bring in some warmer air through Saturday…..with temperatures expected to top out in the mid-upper 50′s today and around 60 tomorrow.

It looks as if we are in for a good soaking this weekend…..with areas around the I-20 corridor getting 1-3″ rainfall totals.  Our friends to the south of I-85 could receive 4″+ totals as the system winds down by Sunday.  It looks now as if none of the area will deal with much in the way of thunder.  The unstable airmass just stays off the coast  through the entire event…..so the best shot at anything strong to severe will be over the central Florida peninsula.  Enjoy today and tomorrow as the weekend looks pretty damp.  High temperatures will dip back into the 40′s on Sunday with cloud cover hanging around as our upper level system wraps in colder air and moves toward the north.

Enjoy your Thursday!

Latest News and the Evening Forecast

A developing upper trough in the southern stream will begin to close off later tomorrow.  In response a surface low pressure system will begin to form in the Gulf of Mexico and allow for showers/thunderstorms to begin to encompass a large portions of the western/central Gulf of Mexico.  Our winds will begin to increase as the low pressure strengths and the pressure gradient tightens Friday evening and Saturday.  Heavy rainfall and gusty winds continue to be our main impacts here across Alabama…..with the outside chance of a strong/severe storm across the south sections.

Temperatures will continue to warm up into the 50′s on Thursday and maybe touching 60 in a few locations on Friday.  Low’s will be around 30 tonight and tomorrow night, but will have a hard time touching the 30′s due to rainfall over the weekend.  This will be a nice break from the frigid conditions that we have dealt with as of late.

On a few notes…Scott Miller, owner and operator of Miller Web Technologies was responsible for our server move.  The website was down due to tremendous overload of our old server.  Our account should have been able to handle the load, but the host company continued to suspend our online account as many of you saw.  Now that we are with Miller Web Technologies, Scott assures us that this won’t be an issue.  If you have any problems with our site during the remainder of the minor fixes in progress, please contact me at brett.adair@alabamastormtrackers.com 

On another bright note…..I have been invited to write for Examiner.com as the Birmingham Weather Examiner.  This is a wonderful opportunity for me, our site, and the viewers.  Hopefully this will only allow us to expand our viewership base and push us to be better forecasters and content providers in the future.  We hope that you will continue to stay with the Alabama Storm Trackers during times of inclement and not-so-inclement weather.  More new features will be coming in the future….so stay tuned!