Kevin Laws is one of the excellent forecasters out at the National Weather Service Birmingham office.
He just penned an excellent mesoscale discussion that is fairly easy to read. I thought you might enjoy it too.
He basically says that a mini-frontal boundary has set up from Columbus MS to Clanton to Auburn. Very unstable air is south of the boundary. Storms will move southeastward along the boundary later today, and storms could fire along it.
Heavy rain, gusty winds, hail and lightning are the primary threat today. Storms that get into the more unstable air will have the potential to produce damaging winds and large hail.
618
FXUS64 KBMX 021508
AFDBMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
930 AM CDT SAT MAY 2 2009
.UPDATE…MESOSCALE UPDATE.
&&
.MESOSCALE DISCUSSION…
WHILE THE SYNOPTIC…NEARLY STATIONARY BOUNDARY LINGERS FROM THE DC
METRO SOUTHWEST TO NEAR DALLAS…HAVE FOCUSED MORE ON THE ONGOING
CONVECTION CLOSER TO HOME. MESOSCALE CONVECTIVE SYSTEMS CONTINUE
FIRING ALONG THE SYNOPTIC BOUNDARY AND SLOWLY PROPAGATING ALONG THE
WEAK NORTHWESTERLY MEAN FLOW. THIS HAS ALLOWED THE MORE SIGNIFICANT
SEVERE AND FLOODING PROBLEMS TO REMAIN TO OUR NORTH…CLOSER TO THE
INITIALIZATION POINTS. EXPECT TODAY TO BE SOMEWHAT SIMILAR…WITH A
FEW EXCEPTIONS.
THE SYNOPTIC TRIGGER POINT CONTINUES TO SLOWLY DRIFT TOWARDS CENTRAL
ALABAMA. THIS WILL BRING BETTER THUNDERSTORM CHANCES FURTHER SOUTH
THAN HAVE BEEN PREVIOUSLY NOTED. THIS WILL ENHANCE THE SEVERE
POTENTIAL…AS INSTABILITY PARAMETERS ARE MUCH GREATER FURTHER
SOUTH…ESPECIALLY IN THE LOW LEVEL LAPSE RATES AND DRIER AIR
ALOFT. I AM ALSO CONCERNED AS A NEW MESOSCALE BOUNDARY HAS NOW
FORMED ACROSS CENTRAL ALABAMA THANKS TO THE EARLIER CONVECTION AND
ENHANCED CLOUD COVER PERSISTENT ACROSS THE NORTHERN COUNTIES. THIS
BOUNDARY CURRENTLY EXISTS FROM AROUND GOLDEN TRIANGLE MS SOUTHEAST
TO NEAR CLANTON AND THEN NEARLY EAST TO JUST NORTH OF AUBURN. IT
WILL BE INTERESTING TO SEE HOW THIS BOUNDARY INTERACTS WITH
APPROACHING CONVECTION FROM THE NORTHWEST…OR IT POSSIBLY COULD
INITIATE ITS OWN CONVECTION LATER THIS AFTERNOON. SOUTH OF THIS
BOUNDARY THE AIRMASS WILL BE EVEN MORE UNSTABLE AS CLOUD COVER IS
QUICKLY ERODING AND THE SURFACE TEMPS ARE NEARLY 10 DEGREES WARMER
AT THIS EARLY HOUR. IT IS ALSO NOTED ON VISIBLE SATELLITE AND RADAR
BRAGG SCATTER…THAT AREAS SOUTH OF THIS NEWLY DEVELOPING BOUNDARY
ARE ALREADY FORMING SOUTHWEST TO NORTHEAST HORIZONTAL CONVECTIVE
ROLL CLOUDS…JUST ANOTHER INDICATION OF THE GROWING
INSTABILITY.
IF STORMS ARE ABLE TO FIRE ALONG THE PREVIOUSLY NOTED SYNOPTIC
BOUNDARY OR THE DEVELOPING MESOSCALE BOUNDARY LATER THIS AFTERNOON
SEVERE WEATHER INCLUDING THE POTENTIAL FOR STRONG GUSTY WINDS AND
HAIL WILL BE THE MAIN THREATS. HEAVY RAIN…INCLUDING THE POTENTIAL
FOR FLOODING WILL ALSO BE A THREAT DUE TO THE WEAK RELATIVE FLOW.
IF STORMS ARE ABLE TO PROPAGATE INTO THE EXTREME SOUTHERN
REGION…SOUTH OF THE MESOSCALE BOUNDARY…THE POTENTIAL EXISTS FOR
EVEN STRONGER STORMS…WITH DAMAGING WINDS AND LARGE HAIL.
IT DOES APPEAR THAT THE THREAT FURTHER SOUTH WILL REMAIN
ISOLATED…DUE TO THE SYNOPTIC SCALE INITIATION POINT REMAINING
SEVERAL HUNDRED KILOMETERS TO THE NORTH AND THE SLOW PROPAGATION
SPEED SOUTHWARD. HOWEVER…THE MESOSCALE BOUNDARY COULD BE THE WILD
CARD AS STORMS APPROACH IT AND AS ITS OWN FIRING MECHANISM. CHECK
BMX GRAPHICAST FOR MESOSCALE ANALYSIS.
17/KLAWS
