286
AWUS01 KWNH 290033
FFGMPD
TNZ000-ALZ000-MSZ000-ARZ000-290600-
MESOSCALE PRECIPITATION DISCUSSION 0149
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
832 PM EDT TUE APR 28 2026
AREAS AFFECTED...EASTERN AR...NORTHERN MS...NORTHWEST
AL...SOUTHWEST TN
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 290030Z - 290600Z
SUMMARY...INCREASING CONVECTIVE COVERAGE WITH STRENGTHENING OF THE
LOW-LEVEL JET, AMPLE MOISTURE AND OCCASIONAL TRAINING/REPEATING
ELEMENTS SUPPORT RATES UP TO 2+"/HR LOCALLY AND WIDELY SCATTERED
SPOTS OF 2-4" INDUCING POSSIBLE INCIDENT(S) OF FLASH FLOODING
THROUGH EARLY OVERNIGHT PERIOD.
DISCUSSION...GOES-E WV SUITE SHOWS BROAD DIFFLUENCE BETWEEN THE
SPLIT IN THE POLAR JET (WHICH IS DEFLECTING NORTHWARD THROUGH THE
OHIO VALLEY) AND THE SUB-TROPICAL JET THAT IS DIVING SOUTH ACROSS
E TX. THIS HAS SUPPORTED SOME BROAD ASCENT AND FAVORABLE
VORTICITY DEVELOPMENT ACROSS E AR IN THE MID-LEVELS TO SUPPORT A
WEAK SURFACE WAVE AND NORTHWARD WARM-ADVECTIVE SHIFT ACROSS
NORTHERN AR. LLJ CONTINUES TO INCREASE IN SPEED AND IS UTILIZING
THE WESTERN FRIDGE OF A SHALLOW OUTFLOW THAT HAS BEEN REINFORCED
BY MULTIPLE ROUNDS OF CONVECTION ACROSS N MS TODAY. DEEP LAYER
MOISTURE IS POOLED ALONG THAT OUTFLOW BOUNDARY AND IS PROVIDING
SOLID FLUX TO DEVELOPING STORMS. HOWEVER, RAP ANALYSIS SHOWS
INCREASING CAPPING ACROSS S AR WITH A REMAINING WEAKLY CAPPED OR
UNCAPPED AREA OF 2000-2500 J/KG OF MLCAPE ACROSS NORTH-CENTRAL AR
ANGLING SOUTHWEST INTO NW MS ATTM. AS SUCH, INCREASING ACTIVITY
IS UTILIZING THE BUOYANCY AND DIVERGENCE ALOFT TO EXPAND IN
COVERAGE AND RAINFALL EFFICIENCY.
OVERALL DEEP LAYER MOISTURE IS AT OR AROUND 2" AND GIVEN THE
VERTICAL ASCENT CAPABILITY AND OVERALL LOW LEVEL MOISTURE
CONVERGENCE/FLUX SHOULD SUPPORT RATES OF SIMILAR VALUES (2"/HR).
THE LIMITING FACTOR IS THE RESIDENCY OF ANY GIVEN CELL, WILL BE
LIMITED DUE TO EAST TO EAST-SOUTHEAST CELL MOTIONS AND FORWARD
PROPAGATION. ORIENTATION OF THE CONVECTIVE CELLS MAY ALLOW FOR
SOME SHORT-TERM TRAINING, BUT OVERALL CELLS WILL BE REPEATING
THROUGH AREAS THAT MAY HAVE SEEN ONE OR TWO EARLIER ROUNDS TODAY
WITH STREAKS OF 1-3" LOCALLY. SO AN ADDITIONAL POTENTIAL FOR 2-3"
WITH A WORST CASE 4" TOTAL, IS IN LINE WITH OR SLIGHTLY EXCEEDS
THE FFG VALUES IN THE AREA OF CONCERN. AS SUCH, A WIDELY
SCATTERED INCIDENT OR TWO OF FLASH FLOODING REMAINS POSSIBLE
THROUGH THE OVERNIGHT PERIOD AS THE WAVE/DIVERGENCE MAXIMA SLIDES
EASTWARD INTO THE DELTA REGION AND EVENTUALLY N MS/AL, THOUGH
INSTABILITY WILL BE STEADILY REDUCING WITH TIME AND THEREFORE
OVERALL COVERAGE AND INTENSITY SHOULD FOLLOW.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...BMX...HUN...JAN...LZK...MEG...
ATTN...RFC...ALR...ORN...TUA...NWC...
LAT...LON 35879144 35759006 35528911 35158827 34788758
34248684 33328717 32928777 32868882 33469023
34119139 34779289 35609302 35839249
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