Graphic for MPD #0509
MESOSCALE PRECIPITATION DISCUSSION 0509
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
603 AM EDT WED JUL 19 2017

AREAS AFFECTED...SOUTHWEST IA...NORTHWEST MO

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

VALID 191002Z - 191302Z

SUMMARY...ISENTROPIC ASCENT AND SLOW CELL MOTIONS WITHIN DEEPLY
SATURATED PROFILE SUPPORTS SHORT-TERM FLASH FLOOD THREAT.

DISCUSSION...EXPERIMENTAL GOES-16 IR LOOP SHOWS A PERSISTENT
CONVECTIVE COMPLEX WITH CYCLING OVERSHOOTING TOPS AS COLD AS THE
-65C ACROSS SW IA INTO N MO.  RAP ANALYSIS DEPICTS A VEERING BUT
STILL STRONG LLJ ACROSS CENTRAL KS INTO NEB GENERALLY INTERSECTING
AN EFFECTIVE WARM FRONT ACROSS SE NEB/NE KS AS 25KTS OF SFC FLOW
ACCELERATES IN THE UPGLIDE TO CONVECT AROUND 850-800MB COINCIDENT
WITH A LOCALIZED POOL OF ELEVATED INSTABILITY IN THE RANGE OF
1500-2000 J/KG...WITH AMPLE MOISTURE ALLOWING FOR TPWS TO EXCEED
2.0".  THIS HAS ALLOWED FOR EFFICIENT RAINFALL PRODUCTION.  TO
EXACERBATE ENVIRONMENTAL CONDITIONS.  MID TO UPPER LEVEL FLOW IS
NICELY DIFFLUENT ALONG NORTHEAST SIDE OF STRONG ANTICYCLONE
ANCHORED OVER NE KS.  MODEST 500-1000MB THICKNESS FIELD IS ALSO
DIFFLUENT SUPPORTING SLACKED FIELD OF PROPAGATION VECTORS.  RECENT
RADAR MOSAIC ALSO SUGGESTS THAT AS THE WAA HAS BEEN SURGING OF
LATE...SOME REDEVELOPMENT UPSTREAM OVER MONTGOMERY/PAGE COUNTIES
WILL TRACK OVER AREAS THAT HAVE RECEIVED UP TO 2" ALREADY.  WET
GROUND CONDITIONS OVER THE LAST FEW WEEKS AND LOWER FFG VALUES
ALSO SUPPORT THE POSSIBILITY OF FLASH FLOODING CONDITIONS EVOLVING
SOON.

OVERALL HI-RES GUIDANCE HAS BEEN POOR TO HANDLE THE MAGNITUDE
LIKELY UNDERESTIMATING LOW LEVEL JET AND AVAILABLE
INSTABILITY...WITH THE RAP FIELDS LIKELY CLOSEST.  FORECAST IS FOR
A SLOW WEAKENING LOW LEVEL JET OVER THE NEXT HOUR OR SO WITH
CONTINUED VEERING...LEAVING A WINDOW FOR AN ADDITIONAL 1-2 HOURS
BEFORE WEAKENING ACROSS N MO.

GALLINA

ATTN...WFO...DMX...EAX...OAX...

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

LAT...LON   41629505 40879405 40449371 40139362 39779359
            39329381 39109450 39749506 40259527 40709549
            41269560 41529565


Last Updated: 603 AM EDT WED JUL 19 2017