452
AWUS01 KWNH 261742
FFGMPD
TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-262340-
MESOSCALE PRECIPITATION DISCUSSION 0531
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
140 PM EDT FRI JUN 26 2026
AREAS AFFECTED...PORTIONS OF THE OZARK PLATEAU INTO THE LOWER OHIO
VALLEY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 261740Z - 262340Z
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WILL BE GRADUALLY
REDEVELOPING AND EXPANDING IN COVERAGE THIS AFTERNOON AND INTO THE
EVENING HOURS. HIGH RAINFALL RATES LOCALLY EXCEEDING 2 INCHES/HOUR
ARE EXPECTED, AND WITH GENERALLY WET ANTECEDENT CONDITIONS AND
HIGH STREAMFLOWS, THERE WILL LIKELY BE NEW AREAS OF FLASH FLOODING.
DISCUSSION...VISIBLE SATELLITE IMAGERY ALONG WITH SURFACE
OBSERVATIONS SHOW A BROAD AREA OF LOW PRESSURE OVER EASTERN KS
WHICH IS ADVANCING SLOWLY OFF TO THE EAST TOWARD AREAS OF WESTERN
MO. THIS IS TRAVERSING A FRONTAL ZONE DRAPED GENERALLY WEST TO
EAST FROM THE CENTRAL PLAINS EASTWARD INTO THE OH VALLEY.
DESPITE SUBSTANTIAL MORNING CLOUD COVER, THE WARM-SECTOR AIRMASS
POOLING ALONG THIS FRONT AND AHEAD OF THE SURFACE LOW HAS BEEN
GRADUALLY DESTABILIZING WITH MLCAPE VALUES OF 500 TO 1000 J/KG
ACROSS CENTRAL MO THROUGH SOUTHERN IL. HOWEVER, MUCH STRONGER
THERMODYNAMICS ARE NOTED OVER THE OZARK PLATEAU WHERE MLCAPE
VALUES HAVE RISEN TO 1500 TO 2000 J/KG. THE ENVIRONMENT IS VERY
MOIST WITH PWS ON THE ORDER OF 1.5 TO 2 STANDARD DEVIATIONS ABOVE
NORMAL WITH VALUES OF 1.8 TO 2.2 INCHES.
THIS VERY MOIST AND INCREASINGLY UNSTABLE AIRMASS WILL BE IN PLACE
AS SOME MODEST, LOW-AMPLITUDE SHORTWAVE ENERGY EMBEDDED WITHIN THE
MID-LEVEL WESTERLY FLOW TRAVERSES THE REGION GOING THROUGH THE
AFTERNOON HOURS. THE RESULT WILL BE THE DEVELOPMENT AND EXPANSION
OF HEAVY SHOWERS AND THUNDERSTORMS THAT WILL BE CAPABLE OF
PRODUCING RAINFALL RATES AS HIGH AS 1.5 TO 2.5 INCHES/HOUR. A
COMBINATION OF WEAK DPVA, LOW-LEVEL MOISTURE CONVERGENCE NEAR AND
SOUTH OF THE FRONT, AND RELATIVELY DIVERGENT FLOW ALOFT WILL HELP
FACILITATE THE CONVECTIVE THREAT. SOME MODEST SHEAR ALSO IS NOTED
WHICH MAY FAVOR SOME RELATIVELY ORGANIZED MULTICELL BANDS OF
HEAVIER SHOWERS AND THUNDERSTORMS THAT MAY SUPPORT THESE HIGHER
RAINFALL RATES.
THE LATEST HRRR GUIDANCE AND THE 12Z HREF/REFS SOLUTIONS SHOW
INCREASING COVERAGE OF CONVECTION OVER THE NEXT SEVERAL HOURS WITH
SOME LOCALIZED RAINFALL TOTALS REACHING 3 TO 4+ INCHES BY EARLY
THIS EVENING. AREAS EAST OF THE OZARK PLATEAU INCLUDING SOUTHEAST
MO (NEAR CAPE GIRARDEAU), SOUTHERN IL (NEAR CARBONDALE), AND
SOUTHERN IN (APPROACHING EVANSVILLE) ARE GENERALLY FAVORED TO SEE
THE HEAVIEST TOTALS FOR THIS NOWCAST PERIOD. HOWEVER, BY EARLY
THIS EVENING, CONVECTION SHOULD DEVELOP AND BECOME INCREASINGLY
MORE FOCUSED ACROSS THE OZARK PLATEAU INCLUDING SOUTHWEST MO,
NORTHERN AR AND BACK INTO NORTHEAST OK.
MOST OF THE REGION IS GENERALLY QUITE SENSITIVE, WITH WET
ANTECEDENT CONDITIONS. THE ADDITIONAL RAINFALL POTENTIAL OVER THE
NEXT SEVERAL HOURS, AND ESPECIALLY BY THIS EVENING, WILL STRONGLY
FAVOR RUNOFF CONCERNS AND A LIKELIHOOD FOR MORE AREAS OF FLASH
FLOODING.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...EAX...ICT...ILX...IND...LMK...LSX...LZK...MEG...
OHX...PAH...SGF...TSA...
ATTN...RFC...KRF...MSR...ORN...TIR...TUA...NWC...
LAT...LON 39139036 39028778 38288575 37268568 36758674
36628738 36308870 35718997 35369071 34899205
34929399 35269514 35799599 36649623 37519554
38469398 38969224
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