Graphic for MPD #0097
 
MESOSCALE PRECIPITATION DISCUSSION 0097
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
354 PM EDT SUN MAY 17 2015
 
AREAS AFFECTED...MID-MISSISSIPPI VALLEY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 171953Z - 180153Z
 
SUMMARY...CONVECTION IS ATTEMPTING TO ORGANIZE IN AN AREA THE
MESOSCALE GUIDANCE IS FALTERING.  WITH SATURATED SOILS, FLASH
FLOODING IS A CONCERN.

DISCUSSION...AN OUTFLOW BOUNDARY/THERMAL DISCONTINUITY LEFT OVER
FROM EARLIER CONVECTION APPEARS TO BE ACTING AS A FOCUS FOR NEW
ACTIVITY ACROSS PORTIONS OF NORTHERN MS AND WESTERN TN.  THE
MESOSCALE QPF GUIDANCE IN THE REGION APPEARS TO BE FAILING,
FOCUSING THE ACTIVITY CLOSE TO 150 MILES WEST OF WHERE IT IS
MATERIALIZING AT THIS TIME.  THE ONLY LOCATION WHERE THEY HAVE
SOME AGREEMENT IN A HEAVY RAINFALL SIGNAL -- A WEAK ONE -- IS NEAR
THE NORTHERN MS/AL BORDER.  VAD WIND PROFILES SHOW BROAD 30-40 KTS
OF 850 HPA INFLOW INTO THE BOUNDARY, NEAR THE MAGNITUDE OF THE
MEAN 850-400 HPA WIND.  CAPE VALUES OF 1000-2000 J/KG HAVE TAKEN
UP RESIDENCE NEAR AND SOUTH OF THE BOUNDARY.  PRECIPITABLE WATER
VALUES OF 1.75" ARE SEEN VIA GPS INFORMATION.

CORFIDI/PROPAGATION VECTORS SUGGEST ORGANIZED THUNDERSTORM
ACTIVITY MAY NOT MOVE VERY FAR -- PERHAPS TO THE EAST AND
NORTHEAST BASED ON THE 1000-500 HPA THICKNESS PATTERN.  THE FLOW
IN THE REGION IS BECOMING MORE UNIDIRECTIONAL OUT OF THE SOUTH TO
SOUTHWEST -- BOTH THE MINIMAL WIND SHIFT WITH HEIGHT AND AMOUNT OF
INSTABILITY AVAILABLE SUGGEST MINIMAL FORWARD PROPAGATION.  AS
TIME WEARS ON, THE MEAN 850-400 HPA FLOW WEAKENS, WHICH SUGGESTS
AN ENHANCEMENT TO THE FLASH FLOOD RISK.  HOURLY RAIN RATES UP TO
2" AN HOUR OUTSIDE OF CELL MERGERS AND AREAS OF EXTENSIVE CELL
TRAINING COULD LEAD TO FLASH FLOODING OVER SATURATED SOILS.

ROTH

ATTN...WFO...BMX...HUN...JAN...LMK...LZK...MEG...OHX...PAH...

ATTN...RFC...LMRFC...OHRFC...SERFC...

LAT...LON   37218668 36498628 35188677 33918797 33358945 
            33249014 33189080 33059181 32939294 33279289 
            34349179 35568984 37138752 


Last Updated: 354 PM EDT SUN MAY 17 2015