038
AWUS01 KWNH 231602
FFGMPD
PAZ000-WVZ000-OHZ000-KYZ000-232000-
MESOSCALE PRECIPITATION DISCUSSION 1365
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1201 PM EDT WED SEP 23 2026
AREAS AFFECTED...SOUTHERN & SOUTHEAST OH...WESTERN HALF OF WV...
FAR SOUTHWEST PA...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 231600Z - 232000Z
SUMMARY...SMALL,RELATIVELY STATIONARY CELLS CAPABLE OF 1.5"/HR AND
2-3" TOTALS ACROSS RUGGED AND SATURATED SOILS SUGGEST SCATTERED
BUT FOCUSED INCIDENTS OF FLASH FLOODING ARE INCREASINGLY POSSIBLE
THIS AFTERNOON.
DISCUSSION...GOES-E WV SUITE SHOWS APPROACHING STRENGTHENING
SHORTWAVE CENTERED NEAR LOUISVILLE, KY STARTING TO DOMINATE THE
OLDER WEAKENING UPPER-LOW CENTER THAT IS RETROGRADING ACROSS NE
OH; HOWEVER, A COMBINATION OF THE UL AND ML WV CHANNELS (6.2 AND
6.9UM RESPECTIVELY) SHOW SOME WEST TO EAST TEMPERATURE GRADIENTS
ACROS THE OHIO RIVER VALLEY INDICATIVE OF A MID-LEVEL WARM FRONTAL
FEATURE, THAT APPEARS TO BE THE FOCUS OF ENHANCED DEEP LAYER
CONVERGENCE. AS SUCH, SCATTERED TO NUMEROUS SHALLOW-TOPPED WARM
CORE THUNDERSTORMS/SHOWERS HAVE BEEN PRODUCING 1.5"+/HR RATES.
LIMITED INSTABILITY BUT SUFFICIENT 500-750 J/KG OF MUCAPE WITH A
BIT OF MID-LEVEL STEEPENED LAPSE RATES HAVE SUPPORTED THESE NARROW
UPDRAFTS. MOISTURE APPEARS A BIT LIMIT IN ANALYSIS FIELDS, BUT
CIRA LPW SUGGESTS SOME ENHANCED ELEMENTS MAY BE SIMILAR TO FURTHER
SOUTH WITH 850-700 AND 700-500MB NOTING A FEW ENHANCED POCKETS TO
SUPPORT MOISTURE FLUX INTO THE UPDRAFTS. DEEP LAYER FLOW BETWEEN
THE STRONGER APPROACHING WAVE AND RETROGRADING OLDER ONE, SUPPORTS
0-10KTS OF STEERING WHILE STILL SUPPORTING MODEST
DIVERGENCE/DIFFLUENCE ALOFT TO MAINTAIN CELLS FOR GREATER THAN ONE
OR TWO UP/DOWNDRAFT CYCLES PROLONGING RESIDENCY. AS SUCH,
LOCALIZED 1.5"/HR RATES FOR 1-2+ HOURS SUPPORT HIGHLY LOCALIZED
2-3" TOTALS. RECENT HEAVY RAINFALL SWATH IS A BIT FURTHER NORTH
(USING 99TH PERCENTILE OF 0-40CM SATURATION RATIOS FROM NASA LIS
PRODUCT SUITE) BUT RUGGED TERRAIN AND SLIGHTLY INCREASED
URBANIZATION IN SW AND FFG VALUES OF 1"/HR AND 1-1.5"/3HRS SUGGEST
FOCUSED SCATTERED INCIDENTS OF FLASH FLOODING REMAIN POSSIBLE.
WHILE GUIDANCE HAS NOT BEEN SUGGESTING ADDITIONAL DEVELOPMENT,
THERE IS SOLID INSOLATION ACROSS SE OH, SW PA AND N WV THAT
INSTABILITY IS CREEPING UP EVEN THOUGH DYNAMIC FORCING IS NOT AS
POTENT AS FURTHER SOUTHWEST OR NORTHWEST (ACROSS N OH). STILL,
SIMILAR PRE-CURSORY AGITATED CU FIELDS AND SMALL TCU HAVE AN
APPEARANCE OF SOME POTENTIAL FURTHER NORTH AND EAST. DEEPER LAYER
MOISTURE PER CIRA LVT OF 50-75 KG/M/S IN THE LOW LEVEL MOISTURE
PLUME FROM THE EAST/SOUTHEAST SUGGESTS A MORE WIDELY SCATTERED BUT
SIMILAR LOW-TOPPED, SLOW MOVING POTENTIAL FOR EFFICIENT RAINFALL
EXISTS THROUGH EARLY AFTERNOON AS WELL.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...CLE...ILN...PBZ...RLX...
ATTN...RFC...TIR...NWC...
LAT...LON 40968106 40648032 40137980 39467984 38848009
38328068 37818160 37968246 38488348 39138347
40368290 40898196
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