WPC Met Watch |
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Mesoscale Precipitation Discussion: #0042 (2018) |
(Issued at 940 PM EST SAT FEB 24 2018
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MPD Selection |
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MESOSCALE PRECIPITATION DISCUSSION 0042
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
940 PM EST SAT FEB 24 2018
AREAS AFFECTED...OH...WRN PA...WV...SRN IN...NRN KY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 250239Z - 250754Z
SUMMARY...FLASH FLOODING WAS ONGOING IN PARTS OF OH/IN/KY AT 02Z.
RAIN RATES LOCALLY EXCEEDING A HALF INCH PER HOUR WILL EXPAND INTO
PARTS OF WV/PA...WITH LOCAL TOTALS TOPPING 1 INCH THROUGH 08Z.
GIVEN ALREADY FULL STREAMS AND LOW TOLERANCE FOR ADDITIONAL
RAINFALL...FLASH FLOODING IS LIKELY.
DISCUSSION...THE OUTLINED AREA FROM NEAR LOUISVILLE KY TO WESTERN
PA...IS LOCATED ALONG AND NORTH OF A LIFTING WARM FRONT THAT AT
00Z WAS ANALYZED ACROSS CENTRAL WV INTO CENTRAL KY. THE STRONGEST
SYNOPTIC DEEP LAYER FORCING WAS NOTED PER GOES-16 LOOPS INDICATING
AN INFLECTION POINT / LEAF AND ASSOCIATED BROAD CONVECTIVE WEDGE
BACK OVER THE OHIO/MISSISSIPPI CONFLUENCE REGION. DEEP CONVECTION
HAD RUN OUT AHEAD OF THIS FORCING...BUT WITH THE MAXIMUM OF HEIGHT
FALLS STILL YET TO COME...EXPECT RAINFALL TO BE SUSTAINED THROUGH
THE NIGHT ALONG AND NORTH OF THE LIFTING WARM FRONT. THE NOSE OF
THE LOW LEVEL JET IS FORECAST TO PUSH THROUGH OH/WV INTO WESTERN
PA BY 08Z.
AT THIS LATITUDE FLOW WAS SO STRONG...0-6 KM MEAN WIND 50-60
KT...THAT CELLS WILL LIKELY FOLLOW THE MEAN WIND AND FORWARD
CORFIDI VECTORS...TOWARD THE NORTHEAST ALONG THE AXIS OF THE
DISCUSSION AREA. ALTHOUGH INSTABILITY WAS LIMITED...A DEEP WARM
CLOUD LAYER EXISTS...WITH THE KILN SOUNDING INDICATING THE
FREEZING LEVEL AROUND 10 KFT AGL...AND -20 C LEVEL MUCH
HIGHER...IN FACT LITTLE HAIL WAS REPORTED WITH THE ENTIRE SEVERE
WEATHER EVENT THUS FAR. RAINFALL EFFICIENCY IS HIGH.
THE HRRR AND THE 00Z WRF-ARW WERE HANDLING THINGS WELL...AND THEY
SUSTAIN RAIN RATES AT LEAST A HALF INCH PER HOUR LOCALLY...THROUGH
0830Z. TRAINING SMALL SCALE CONVECTIVE CELLS COULD BOOST TOTALS TO
NEAR 2 INCHES LOCALLY. FLASH FLOOD GUIDANCE IS LOW ENOUGH TO BE
EXCEEDED...AND GIVEN THE ANTECEDENT CONDITIONS...ADDITIONAL
FLOODING AND LOCAL FLASH FLOODING APPEARS LIKELY REGARDLESS.
BURKE
ATTN...WFO...CLE...CTP...ILN...IND...JKL...LMK...PBZ...RLX...
ATTN...RFC...MARFC...OHRFC...
LAT...LON 41738058 41377801 40727804 39617976 38768171
38098404 38128582 38578673 39408576 40268401
Last Updated: 940 PM EST SAT FEB 24 2018
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