MESOSCALE PRECIPITATION DISCUSSION 0014
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
912 AM EST THU JAN 21 2016
 
AREAS AFFECTED...N LOUISIANA...NE TEXAS...S ARKANSAS...W CENT
MISSISSIPPI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 211412Z - 212012Z
 
SUMMARY...PERSISTENT ISENTROPIC LIFT FOR CONVECTIVE DEVELOPMENT
NORTH OF FRONT...PRECEDING STRONGER SQUALL LINE LATER TODAY
LEADING TO POTENTIAL FOR ISOLATED FLASH FLOODING CONCERNS. 

DISCUSSION...WV LOOP SHOWS WELL DEFINED UPPER LOW OVER KS WITH
DEEPENING SHORTWAVE DIGGING ACROSS TX PANHANDLE...INCREASING
SHORTWAVE RIDGING ACROSS E TX/N LA; ALONG WITH SUBTROPICAL RIDGE
AXIS SHIFTING ACROSS THE CENTRAL GULF COAST...LEADING TO LARGE
SCALE INCREASING DIVERGENCE/ DIFFLUENCE ACROSS THE DISCUSSION
AREA.  IN THE LOWER LEVELS...WEAK SURFACE WAVE IS EXPECTED TO
RAPIDLY DEEPEN UNDER INCREASED DPVA AND STRENGTHENING COLD
ADVECTION ACROSS OK/TX...COINCIDENTALLY INCREASING WARM SECTOR LOW
LEVEL FLOW TO 30-35KT...PROVIDING INCREASING MST FLUX WITH TPWS
CURRENTLY NEAR 1" AND SURFACE TDS IN THE LOW MID 60S TO BE
ISENTROPICALLY LIFTED ACROSS AN W-E STATIONARY FRONT FROM KOCH TO
KIER TO KHEZ...FOR SOME MODERATE ELEVATED INSTABILITIES WITH
MUCAPES OF 500-1000 J/KG.  THIS HAS BEEN ENOUGH TO SUPPORT
CONVECTIVE DEVELOPMENT JUST SOUTH OF THE FRONT AND LIFT ACROSS THE
BOUNDARY WITH SOME RIGHT MOTION WITH SOME ISOLATED SUPERCELLS.  

GIVEN ORIENTATION OF THE SE PROGRESSION/DIGGING OF THE SHORTWAVE
AND DOWNSTREAM RIDGING ALOFT...SHOULD SUPPORT KEEPING THE
STATIONARY FRONT FROM LIFTING NORTH TOO MUCH PROVIDING A CORRIDOR
OF INCREASED PRECIPITATION ACROSS N LA INTO W CENTRAL MISSISSIPPI
WHERE UPSTREAM DEVELOPING WARM SECTOR CELLS COULD REACH AND SHIFT
EASTWARD WITHIN THE BROADER/MORE MODERATE SHOWERS FROM PERSISTENT
ISENTROPIC ASCENT.  THIS ALONE IS NOT SIGNIFICANT ENOUGH IN RATE
MAGNITUDE OR LONGER DURATION TERM TOTALS TO PRODUCE FLOODING
SITUATION GIVEN THE HIGHER FFG VALUES BUT WILL HELP TO REDUCE THEM
IN ADVANCE OF THE MORE ROBUST/STRONGER CELLS THAT WILL DEVELOP
ALONG THE COLD FRONT AND WILL SLOWLY SHIFT EASTWARD.   THE HI-RES
CAMS ARE A BIT SCATTERED WITH THE BEST AXIS OF THE HIGHER
PRECIPITATION...WITH VARIATION NORTH TO SOUTH.  THE ARW APPEARS TO
BE BEST ORIENTED WITH CURRENT ONGOING CONVECTION WITH TOTALS IN
THE 2-3" RANGE OVER THE NEXT 6HRS.  THIS IS SUPPORTED BY THE NMMB
AND ESRL EXP. HRRR AND THE RECENT FEW HRRR RUNS...THOUGH A BIT
FURTHER NORTH OR SOUTH RESPECTIVE DUE TO DIFFERENCES IN PLACEMENT
OF THE STATIONARY FRONT.     


GALLINA

ATTN...WFO...JAN...SHV...

ATTN...RFC...LMRFC...WGRFC...

LAT...LON   33149092 32979012 32389006 31759057 31569127 
            31799389 32309452 32779419 33069249