WPC Met Watch |
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Mesoscale Precipitation Discussion: #0238 (2017) |
(Issued at 533 PM EDT FRI MAY 19 2017
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MPD Selection |
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MESOSCALE PRECIPITATION DISCUSSION 0238
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
533 PM EDT FRI MAY 19 2017
AREAS AFFECTED...PORTIONS OF OK & NORTHERN TX
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 192132Z - 200332Z
SUMMARY...ELEVATED CONVECTION ACROSS OK IS BEGINNING TO EXPAND IN
COVERAGE. HOURLY RAIN RATES UP TO 2", WITH LOCAL AMOUNTS OF 4",
COULD CAUSE ISSUES OVER SATURATED SOILS.
DISCUSSION...THE 21Z MESOANALYSIS INDICATES A MESOSCALE WAVE NEAR
BRECKENRIDGE TX WHICH IS SUPPORTING ELEVATED CONVECTION THAT IS
BEGINNING TO SHOW TRAINING CHARACTERISTICS ACROSS NORTH-CENTRAL TX
AND SOUTHEAST OK. A SECOND WAVE EXISTS SOUTHEAST OF LUBBOCK TX IN
THE THERMAL FIELD. PRECIPITABLE WATER VALUES OF ~1.5" EXIST HERE,
WITH INFLOW AT 850 HPA OF 25-40 KTS INDICATED ON REGIONAL VAD WIND
PROFILES. BULK SHEAR IN THE 0-6 KM LAYER IS 30-60 KTS, MORE THAN
ENOUGH FOR ORGANIZED CONVECTION. CIN REMAINS IN THE VICINITY OF
MESOSCALE BOUNDARIES ACROSS THE AREA, THOUGH THE CONVECTION ITSELF
LIES NEAR A SURFACE CONVERGENCE ZONE IN THE WIND FIELD BEHIND THE
COLD POOL.
THE 12Z GFS-BASED GALVEZ-DAVISON INSTABILITY INDEX INDICATES
CONTINUED CONVECTIVE EXPANSION IS PROBABLE, WITH VALUES BROACHING
35 IN NORTHEAST TX BY 03Z. CIN COULD ERODE SOMEWHAT IN THE NEXT
FEW HOURS PER RAP-BASED FORECASTS, WHICH WOULD ALLOW A COLD FRONT
MOVING IN FROM THE WEST TO SPUR NEW CONVECTION IN THE MPD AREA.
ELEVATED CONVECTION SHOULD SHIFT SOUTHEAST AT 10-15 KTS AS THE
RESPONSIBLE BOUNDARY AT 850 HPA MOVES EASTWARD. UNTIL THAT TIME,
TRAINING CONVECTION COULD LEAD TO HOURLY RAIN RATES UP TO 2", WITH
THE MESOSCALE GUIDANCE SHOWING A GOOD SIGNAL FOR LOCAL AMOUNTS TO
4". CONSIDERING RECENT RAINS, SOILS ARE PARTIALLY SATURATED.
FLASH FLOODING IS CONSIDERED POSSIBLE.
ROTH
ATTN...WFO...FWD...LUB...OUN...SGF...SHV...SJT...TSA...
ATTN...RFC...ABRFC...LMRFC...WGRFC...
LAT...LON 36889497 36499437 35489426 34169513 33259630
32729788 33280088 35269855 35979754 36879603
Last Updated: 533 PM EDT FRI MAY 19 2017
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