Flash Flood Guidance
Issued by NWS

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000
AWUS01 KWNH 250527
FFGMPD
OKZ000-KSZ000-COZ000-NMZ000-251100-

MESOSCALE PRECIPITATION DISCUSSION 0823
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
126 AM EDT MON SEP 25 2017

AREAS AFFECTED...SOUTHWEST KS...SOUTHEAST CO...W OK
PANHANDLE...NORTHEAST NM

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 250525Z - 251100Z

SUMMARY...POSSIBLE FLASH FLOODING THREAT MAY EVOLVE DUE TO
TRAINING WITH 2-3" TOTALS POSSIBLE OVER AREAS WITH SATURATED SOILS
AND LOWER FFG VALUES.

DISCUSSION...GOES-16 6.9UM AND REGIONAL RADAR MOSAIC DEPICT A
SHORTWAVE LIFTING NORTHEAST ACROSS NW KS AT THIS TIME WITH A
DRAPED TROF ANGLING BACK TOWARD SE CO GENERALLY COINCIDENT WITH
SURFACE FRONT.  CIRA LPW LOOPS AND 00Z DDC/AMA RAOBS DENOTE THE
MAIN DEEP MOISTURE AXIS IS DISPLACED WELL EAST AS MID TO UPPER
LEVEL AIR ABOVE 7H IS QUITE DRY.  EVEN THOUGH DEEP MOISTURE IS
COMPROMISED...SFC ANALYSIS DENOTES BROAD AREA OF SOUTH-SOUTHEAST
AND SOUTHEASTERLY 15-20KTS OF MID TO UPPER 60 TDS ARE CONVERGING
NEARLY ORTHOGONAL TO THE FRONTAL BOUNDARY.  THIS WHILE 850MB 30KT
SOUTHERLY LLJ WILL ALSO MAINTAIN STRONG ASCENT/MOISTURE AND
INSTABILITY ADVECTION INCREASING SOME RAINFALL EFFICIENCY.  THIS
ALLOWS FOR TPW OF UP TO 1.25"...AND LIKELY TO SUPPORT RATES TO
THAT LEVEL GIVEN AVAILABLE INSTABILITY (1000-2000 J/KG MUCAPES
FROM NM/TX BORDER TO SW KS) FOR SUSTAINING UPDRAFTS.

UPSTREAM WV DEPICTS A STRETCHED OUT POSITIVE TILT SHORTWAVE
CROSSING S CO/N NM...HELPING WITH UPPER LEVEL SHORTWAVE RIDGING
AND SLIGHTLY INCREASED DIFFLUENCE.
STRONGER MID-LEVEL INFLOW (7-5H) BACKBUILDING ALONG THE FRONTAL
BOUNDARY CAN BE EXPECTED PERHAPS AS FAR SE AS NE NM.
10.3UM CLEAR IR AND DDC/PUB RADARS SHOW THIS SOUTHEAST BUILDING
WITH GENERAL COOLING TOPS TOWARD APPROACHING CLUSTER OVER W
HARDING COUNTY NM.  WITH BACKBUILDING AND MEAN FLOW GENERALLY
PARALLEL TO THE FRONTAL BOUNDARY THERE IS AN AXIS FOR TRAINING AND
THE POTENTIAL FOR RAINFALL TOTALS OF 2-3" THROUGH 12Z...IN LINE
WITH RECENT HRRR/ESRL HRRRV3 AND 00Z ARW.  THIS MAY LEAD TO LOW
END FLASH FLOOD RISK MAINLY GIVEN THE LOW FFG VALUES IN THE
VICINITY AS WELL AS SOME LOCATIONS THROUGH WEST CENTRAL KS ALREADY
RECEIVING 1-2" THROUGH EARLIER CONVECTIVE ROUNDS.

HOWEVER...CONFIDENCE IN THIS EVOLUTION IS NOT PARTICULARLY HIGH
EVEN WITH SUPPORT OF RELIABLE GUIDANCE.  THIS IS MAINLY DUE TO THE
FACT OF THE VERY DRY AIR ALOFT AND THE POSSIBILITY OF COLD POOL
GENERATION.  RAPID COLD POOL GENERATION WILL LEAD TO OUTFLOW
BOUNDARIES THAT WILL  DISRUPT TRAINING AXIS/CORRIDOR AS CELLS
PROPAGATE EAST OR SOUTHEAST LIMITING THE TOTALS AND OBVIOUSLY
FLOODING RISK.

GALLINA

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ABQ...AMA...DDC...GLD...PUB...

ATTN...RFC...ABRFC...MBRFC...

LAT...LON   39500125 39340023 38309989 37400071 36680278
            36920378 38560205



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