045
AWUS01 KWNH 112320
FFGMPD
VAZ000-WVZ000-TNZ000-KYZ000-INZ000-120500-
MESOSCALE PRECIPITATION DISCUSSION 1014
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
720 PM EDT TUE AUG 11 2026
AREAS AFFECTED...SOUTH-CENTRAL IND...CENTRAL & EASTERN
KY...WESTERN VA...NORTHEAST TN...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 112320Z - 120500Z
SUMMARY...REPEATING CELLS ALONG OLD OUTFLOW BOUNDARY WITH STRONG
UPSTREAM DEVELOPING BOW/CLUSTER TO ADD SUB-HOURLY 1-1.5" TOTAL MAY
RESULT IN SCATTERED SPOTS OF 2-3" RESULTING IN LOCALIZED FLASH
FLOODING ESPECIALLY NEAR URBAN CENTERS AND MORE RUGGED TERRAIN
DISCUSSION...ACTIVE PATTERN OF MULTIPLE QUICK MOVING BOW ECHOES
CONTINUES TO REPEAT THROUGH THE OHIO RIVER VALLEY INTO THE
CUMBERLAND PLATEAU. THE SECOND MCS IS CURRENTLY CROSS THE CENTRAL
APPALACHIANS FROM S WV INTO W VA CONTINUING SEVERE WINDS
ACCOMPANIED BY INTENSE BURST OF HEAVY RAINFALL, TYPICALLY BETWEEN
1-1.5" IN LESS THAN 30-45 MINUTES. THIS IS IN THE WAKE OF AN
INITIAL DECAYED MCS THAT LOWERED FFG ACROSS MUCH OF THE AREA WITH
LINGERING 100-200 CFS/SQ.MI WITHIN MRMS FLASH UNIT STREAM FLOWS,
BRINGING THEM BACK UP TO 200-400 AS THE BOW PASSES, REAGGRAVATING
FLOODING CONDITIONS.
IN THE WAKE OF THE SECOND MCS, THE COLD POOL HELPED TO PUSH
OUTFLOW BOUNDARY FURTHER SOUTHWEST THAN INITIAL EXPECTED THROUGH
SOUTHERN IND INTO CENTRAL KY. VWP DEPICTS SURFACE TO 925 WINDS
HAVE BACKED TO SOUTHWESTERLY AND GENERALLY ORTHOGONAL TO THE
BOUNDARY, AS SUCH SCATTERED BUT SLIGHTLY MORE ELEVATED CELLS HAVE
BEEN FILLING IN BETWEEN THE TRAILING FLANK NEAR PERRY/LESLIE
COUNTY, BACK ACROSS CENTRAL KY TOWARD CASEY TO MEADE COUNTY AND
ACROSS THE OHIO RIVER TO CRAWFORD COUNTY, IND. THE
ADVECTED/ISENTROPICALLY ASCENDING AIR REMAINS VERY UNSTABLE WITH
MLCAPE OVER 3500 J/KG ALLOWING FOR SCATTERED CONVECTIVE INITIATION
ALONG THE LINE. UPDRAFTS ARE GENERALLY NARROW DUE TO WEAK
INFLOW/ASCENT, HOWEVER, A STRONGER CLUSTER OVER MARTIN COUNTY IS
STARTING TO BOW OUT AS WELL GIVEN THE STRONG REAR-INFLOW JET OVER
50-60KTS. AS SUCH, STRONGER COLD POOL IS INCREASING FORWARD SPEED
OF THE BOW AND INCREASING MOISTURE CONVERGENCE TO ONCE AGAIN
RESULT IN A QUICK 1-1.5" TOTAL IN LESS THAN 30-45 MINUTES.
THIS CLUSTER SHOULD INTERSECT AREAS AFFECTED BY THE WEAKER
ISENTROPICALLY FORCED SCATTERED CELLS WILL RESULT IN SCATTERED
POCKETS OF 2-3" TOTALS AND GIVEN THE HEAVY QUICK BURST TO END, MAY
RESULT IN LOCALIZED FLASH FLOODING CONDITIONS GIVEN SATURATED
GROUNDS. THIS WOULD ONLY BE EXACERBATED IN URBAN/HYDROPHOBIC
SURFACES. UNLIKE FURTHER NORTH WITH THE SECOND MCS, THIS THIRD
BOWING MCS IS MOVING THROUGH AREAS NOT AFFECTED BY THE FIRST OR
SECOND ROUND, SO INCIDENTS OF FLASH FLOODING MAY BE MORE ISOLATED
TO SCATTERED UNTIL REACHING THE MORE RUGGED TERRAIN OF THE
CUMBERLAND PLATEAU TOWARD 03Z. AS SUCH, FLASH FLOODING IS
CONSIDERED POSSIBLE THIS EVENING.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ILN...IND...JKL...LMK...MRX...PAH...RLX...RNK...
ATTN...RFC...ORN...TIR...NWC...
LAT...LON 39168674 38828547 38498464 38198367 37878289
37628185 37508103 37178054 36278228 35698375
36618467 37348614 38258716 38728746 39088743
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