WPC Met Watch |
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Mesoscale Precipitation Discussion: #0897 (2017) |
(Issued at 405 PM EDT SAT OCT 21 2017
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MPD Selection |
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MESOSCALE PRECIPITATION DISCUSSION 0897
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
405 PM EDT SAT OCT 21 2017
AREAS AFFECTED...EASTERN KS...NORTH CENTRAL OK...NORTHWEST MO
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 212005Z - 220115Z
SUMMARY...SW TO NE TRAINING AHEAD OF SLOW EASTWARD MOVING FRONT
MAY POSE LOCALIZED 2-4" TOTALS OVER SHORT DURATION SUGGESTING
ISOLATED FLASH FLOODING POSSIBLE THIS EVENING.
DISCUSSION...19Z MESOANALYSIS DEPICTS A WELL DEFINED COLD
FRONT/WIND SHIFT EXTENDING FROM NO W MN INTO E NEB BEFORE ANGLING
WSW ACROSS CENTRAL KS TOWARD NORTHWEST OK. GOES-16 VISIBLE
IMAGERY/RGB ALONG WITH WV SUITE AND SURFACE ANALYSIS DENOTE
CONFLUENCE OF MULTIPLE AIR MASS STREAMS ACROSS NORTHERN OK INTO W
KS WITH DEEPEST MOISTURE INDICATED BY 65+F SFC TDS ABOUT A COUNTY
WEST OF THE COLD FRONT WITH SUFFICIENT MOISTURE CONVERGENCE TO
BREAK WEAK CAP ACROSS E KS WHILE STILL NOT SUFFICIENT ACROSS N OK
JUST YET PER MIXED LAYER INVERSION AT 825MB PER 18Z LMT SOUNDING.
AS THE COLD FRONT ALIGNS WITH THE DEEPER MOISTURE AND ERODES THE
CAP FURTHER...CURRENT CONVECTIVE CORES SHOULD INCREASE IN SIZE AND
DEPTH AS WELL AS EXPANDING INTO N OK IN THE NEXT HOUR OR SO.
INCREASED DEPTH/DEEPER MOISTURE POOL SHOULD ALLOW FOR INCREASED
RAIN RATES UP TO 1.5-2"/HR. FURTHER NORTH INTO N MO/SW
IA...INSTABILITY IS A BIT MORE LIMITED OVERALL WITH MLCAPES BELOW
1000 J/KG (OPPOSED TO UP TO 2000 J/KG ACROSS S CENTRAL KS/N OK).
DEEP CLOUD BEARING MEAN FLOW IS GENERALLY SW AND FAIRLY PARALLEL
TO THE FRONT...HOWEVER...EASTWARD ACROSS EASTERN KS/W MO/NE
OK...SIGNIFICANT 500-1000MB THICKNESS DIVERGENCE EXISTS LIMITING
PROPAGATION VECTORS TO THE EAST BELOW 10KTS. AS SUCH CONVENTION
WILL GENERALLY FAVOR THE OVERALL EASTWARD MOTION SUPPORTED BY THE
HEIGHT FALLS AND CONVERGENCE ALONG THE COLD FRONT. THIS ALLOWS
FOR SOME DURATION OF CELLS TRAINING NEWARD ALONG THE FRONT FOR A
HOUR OR TWO SUPPORTING RAINFALL TOTALS OF 2-3" WITH POTENTIAL FOR
ISOLATED 4". HI-RES CAMS ARE QUITE AGREEABLE WITH THE
AFOREMENTIONED EVOLUTION IN PLACEMENT/TIMING AND TOTALS TO HAVE
FAIRLY HIGH CONFIDENCE IN THIS UNFOLDING.
FAIRLY DRY CONDITIONS MAY ALLOW FOR GREATER GROUND
ABSORPTION...BUT THE SHEAR RATE IN LESS THAN 3HRS IS POSSIBLE TO
LEAD TO A GOOD AMOUNT OF RUNOFF AND LOCALIZED FF CONDITIONS MAY
OCCUR. THE GREATEST THREAT WOULD LIKELY BE IN URBAN CENTERS AS
WELL AS SOUTHERN FLINT HILLS IN KS FROM ICT TO CNU GIVEN WET
GROUND CONDITIONS FROM LAST WEEKEND'S CONVECTION (AHPS 7DAY
ANOMALIES 300-400% OF NORMAL)
GALLINA
ATTN...WFO...EAX...ICT...OUN...SGF...TOP...TSA...
ATTN...RFC...ABRFC...MBRFC...
LAT...LON 40499443 40209296 38039460 36259656 36529866
38099728 39879539
Last Updated: 405 PM EDT SAT OCT 21 2017
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