810
AWUS01 KWNH 162118
FFGMPD
KSZ000-NEZ000-COZ000-170317-
MESOSCALE PRECIPITATION DISCUSSION 1095
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
518 PM EDT TUE SEP 16 2025
AREAS AFFECTED...SOUTHWESTERN NEBRASKA, NORTHWESTERN KANSAS
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 162117Z - 170317Z
SUMMARY...SLOW-MOVING CONVECTION CONTINUES TO DEEPEN ACROSS THE
DISCUSSION AREA, WITH AREAS OF 1+ INCH/HR RATES NOTED BENEATH THE
STRONGEST STORMS. AREAS OF FLASH FLOODING ARE POSSIBLE THROUGH
03Z/10P CDT.
DISCUSSION...SCATTERED THUNDERSTORMS WERE INCREASING IN COVERAGE
ACROSS THE DISCUSSION AREA OVER THE PAST HOUR. THE STORMS APPEAR
TO BE FOCUSED ALONG LOW-LEVEL CONVERGENCE NEAR AN APPARENT WEAK
BOUNDARY (WIND FIELDS SHIFTING FROM SOUTHERLY TO EASTERLY ALONG AN
AXIS FROM NEAR HOLYOKE, CO TO NEAR HEBRON, NE. ALONG THIS
BOUNDARY, 1-1.2 INCH PW VALUES, 2000+ J/KG MLCAPE, AND STEEP LAPSE
RATES ALOFT WERE ALLOWING FOR INTENSE UPDRAFTS AND LOCALLY HEAVY
RAINFALL. MOST STORMS WERE DRIFTING NORTHWARD AMID MODEST DEEP
LAYER FLOW, ALTHOUGH A CELL NEAR MCCOOK, NE HAS ANCHORED ALONG
THIS BOUNDARY AND SLOWED SUBSTANTIALLY WHILE EXHIBITING
BACKBUILDING CHARACTER. RAIN RATES APPEAR TO BE AT A PEAK NEAR
THIS STORM (EXCEEDING 1.5 INCH/HR), AND IT CANNOT BE RULED OUT
THAT OTHER STORMS EXHIBIT THIS SAME BEHAVIOR IN THE SHORT TERM.
STORMS APPEAR TO BE AIDED BY ASCENT ALOFT ASSOCIATED WITH A WEAK
MID-LEVELS SHORTWAVE TROUGH EVIDENT IN WATER VAPOR IMAGERY OVER
NORTHEASTERN COLORADO. THIS WAVE WILL TAKE SEVERAL HOURS TO
TRAVERSE THE REGION, AND ASCENT FROM THIS FEATURE SHOULD CONTINUE
INTERACTING WITH THE STRONG INSTABILITY IN PLACE TO KEEP FOSTERING
DEEP CONVECTIVE DEVELOPMENT. SOUTHERLY 850MB FLOW INTO THE AREA
SHOULD CONTINUE TO MAINTAIN THE POOL OF INSTABILITY. SCATTERED,
SLOW-MOVING STORMS ARE EXPECTED TO CONTINUE THROUGH AT LEAST
03Z/10P CDT THIS EVENING ACROSS THE REGION. LOCAL RAIN RATES
EXCEEDING 1.5 INCHES/HR SHOULD READILY EXCEED FFG THRESHOLDS.
FLASH FLOODING IS PROBABLE ON AT LEAST AN ISOLATED BASIS.
COOK
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...BOU...DDC...GID...GLD...ICT...LBF...
ATTN...RFC...KRF...NWC...
LAT...LON 41370236 40999943 39999801 38879816 39580196
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