Graphic for MPD #0225

MESOSCALE PRECIPITATION DISCUSSION 0225
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1154 AM EDT WED MAY 17 2017

AREAS AFFECTED...EASTERN NEBRASKA AND WESTERN IOWA

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

VALID 171553Z - 171953Z

SUMMARY...NEW CONVECTION IS EXPECTED TO DEVELOP IN THE LATE
MORNING/EARLY AFTERNOON AFFECTING AREAS WITH WET ANTECEDENT
CONDITIONS, RESULTING IN POSSIBLE FLASH FLOODING.

DISCUSSION...GOES VISIBLE IMAGERY SHOWS AN AREA OF ERODING CLOUD
COVER FROM NORTHEAST KANSAS TO SOUTHWESTERN IOWA.  CONVECTIVE
INITIATION HAS BEGUN ACROSS NORTH-CENTRAL KS AS THE SPC
MESOANALYSYS SHOWING SURFACE BASED INSTABILITY TO BE INCREASING
ACROSS THE REGION DUE TO DAYTIME HEATING. THE 12Z OMAHA NEBRASKA
SOUNDING SHOWS A SATURATED ENVIRONMENT WITH MODEST UNIDIRECTIONAL
FLOW. PRECIPITABLE WATER VALUES OF 1.00-1.25 INCHES...WHILE NOT
OVERLY ROBUST...SHOULD SUPPORT RAINFALL RATES OF UP TO 1.5 INCHES
PER HOUR.

CONVECTIVE PROPAGATION VECTORS IN THE VICINITY OF THE SURFACE LOW
WILL BE ON THE ORDER OF 5 TO 10 KTS DUE TO WEAK MEAN 850-200 HPA
WINDS NEAR THE DEEP-LAYERED CYCLONE INDICATING THAT SLOWER STORM
MOTIONS AND SOME DEGREE OF BACKBUILDING WOULD BE POSSIBLE AS THE
SURFACE LOW TRACKS NORTHEASTWARD ACROSS THE REGION THIS AFTERNOON.
 BULK SHEAR IN THE 0-6 KM LAYER IS 30-50 KTS, WHICH SHOULD ALLOW
FOR ORGANIZED CONVECTION, WITH POSSIBLY SOME EMBEDDED
MESOCYCLONES.  FLASH FLOOD GUIDANCE IS EXTREMELY LOW ACROSS THE
REGION DUE TO RECENT RAINFALL WITH VALUES RANGING FROM 0.75 TO
1.50 INCHES OVER A THREE HOUR PERIOD. GIVEN THE
ENVIRONMENT...FLASH FLOODING WILL BE POSSIBLE.

KREKELER

ATTN...WFO...DMX...EAX...FSD...GID...MPX...OAX...

ATTN...RFC...MBRFC...NCRFC...

LAT...LON   43949567 43649400 41789357 40029660 40669831
            42589741


Last Updated: 1154 AM EDT WED MAY 17 2017