Graphic for MPD #0033
 
MESOSCALE PRECIPITATION DISCUSSION 0033
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
639 AM EST SAT JAN 21 2017
 
AREAS AFFECTED...ERN LA...SRN MS...CENTRAL AND SRN AL...CENTRAL
GA...NW FL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 211139Z - 211539Z
 
SUMMARY...

DISCUSSION...AN ORGANIZED AND SLOWLY PROGRESSIVE LINEAR CONVECTIVE
SYSTEM WITH WARM ADVECTION WING WILL CONTINUE TO PRESS THROUGH THE
SOUTHEAST STATES. THE HEAVIEST PRECIPITATION...ON THE ORDER OF 2.0
TO 3.5 INCHES...SHOULD FALL SOUTH OF BIRMINGHAM AND IN THE
SOUTHERN PORTION OF ATLANTA... STRETCHING BACK TO NEW
ORLEANS...AND INCLUDING MUCH OF SOUTHERN MS/AL TO CENTRAL GA. 

AT 1130Z THE INTENSITY OF RADAR REFLECTIVITY AND BREADTH OF HEAVY
RAINFALL AS ESTIMATED BY DUAL-POL HYDROMETEOR CLASSIFICATION SPOKE
TO THE ENVIRONMENT... WHICH WAS CHARACTERIZED BY STRONG
FORCING...MODERATE INSTABILITY...AND STRONG LOW LEVEL MOISTURE
FLUX. WPC HAD BEGUN TO ANALYZE A SURFACE FRONT ALONG THE GULF
COAST IN A REGION WHERE ENERGETIC SOUTHWEST FLOW HAD ESTABLISHED A
MID LEVEL BAROCLINIC GRADIENT. LINEAR CONVECTION FROM CENTRAL AL
TO EASTERN LA WILL CONTINUE TO BE SUPPORTED BY HEIGHT FALLS
PRESSING EAST AT THE LEADING EDGE OF AN UPPER TROUGH...AND UPGLIDE
ON THE 300 K SURFACE PER RAP SOUNDINGS WILL SUPPORT NUMEROUS
THUNDERSTORMS AHEAD OF THE MAIN LINE ACROSS EASTERN AL/CENTRAL GA.
CELL MERGERS WITHIN THIS REGION WILL ENHANCE SHORT TERM RAIN
RATES. FARTHER DOWN THE LINE TO THE SOUTHWEST THE EVENT WILL BE A
BIT MORE CONTAINED WITHIN THE SINGLE MCS AND TRAILING STRATIFORM
REGION...BUT WITH POTENTIAL FOR ALL OF THIS ACTIVITY TO PRODUCE
2-INCH PER HOUR RAIN RATES PER RADAR ESTIMATES AND THE AVAILABLE
MESONET AND CITIZEN GAUGES.

MUCH OF THE HI-RES GUIDANCE WAS EITHER ON THE SLOW SIDE OR WAS
UNDERPLAYING THE INTENSITY IN THE MIDDLE AND SOUTHERN PORTION OF
THE LINEAR FEATURE. THE NSSL WRF AND SPC WRF PERHAPS HAD THE BEST
HANDLE AT 11Z...AND SUGGEST 2 TO 3.5 INCH AMOUNTS WILL BE COMMON
IN THE DISCUSSION AREA. THE SHORT TERM INTENSITY MAY LEAD TO FLASH
FLOODING DESPITE HIGH GUIDANCE VALUES.

BURKE

ATTN...WFO...BMX...CAE...FFC...JAN...LIX...MOB...TAE...

ATTN...RFC...LMRFC...SERFC...

LAT...LON   33648345 33288212 32498242 31848399 30238874 
            29909060 30589032 32658740 33568537 


Last Updated: 639 AM EST SAT JAN 21 2017