WPC Met Watch |
|
Mesoscale Precipitation Discussion: #0290 (2014) |
(Issued at 151 PM EDT MON AUG 18 2014
) |
|
MPD Selection |
|
|
|
MESOSCALE PRECIPITATION DISCUSSION 0290
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
151 PM EDT MON AUG 18 2014
AREAS AFFECTED...SOUTHERN TN/NORTHEASTERN MS/NORTHERN
AL/NORTHWESTERN GA...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 181751Z - 182151Z
SUMMARY...CONVECTION FIRING NORTH AND EAST OF AN MCV HAS BEGUN
MOVING INTO AN AREA WHICH EARLIER SAW VERY HEAVY RAINFALL.
DIMINISHED FFG VALUES SUGGEST FLASH FLOODING WILL BE LIKELY IN
SOME OF THE HEAVIER PRECIPITATION CORES.
DISCUSSION...A 17Z TEMPERATURE ANALYSIS SHOWED AN EXPANDING WARM
SECTOR ACROSS WESTERN TN WHERE AGITATED CU WERE OBSERVED.
ADDITIONALLY A MORE EXPANSIVE AXIS OF CONVECTION HAS DEVELOPED
ALONG A WEST-EAST LINE WITH THE UPDRAFTS GROWING RAPIDLY PER THE
EXPERIMENTAL 1 MINUTE RAPID SCAN VISIBLE IMAGERY. THE MEAN
STEERING FLOW REMAINS WEST TO EAST WHICH SUGGESTS THE ACTIVITY
WILL SLIDE EASTWARD INTO CENTRAL TN DURING THE NEXT COUPLE OF
HOURS. RAP FORECAST SOUNDINGS SHOW STORM INFLOW BEING NEARLY EQUAL
IN DIRECTION AND MAGNITUDE WHICH MAKES TRAINING CONVECTION
POSSIBLE THIS AFTERNOON. EXPECT THE EXPANDING CU FIELD TO CONTINUE
TO GROW GIVEN THE AXIS OF 1000 TO 2000 J/KG OF MLCAPE OBSERVED IN
THE 17Z RAP OBJECTIVE ANALYSIS. THE ENVIRONMENT REMAINS QUITE
MOIST WITH MIXING RATIOS OF AROUND 18 G/KG ACROSS MUCH OF TN AND
DOWN INTO NORTHERN MS/AL. THUS ANY AXIS OF HEAVIER RAINFALL SHOULD
CARRY FAIRLY HEFTY RAINFALL RATES. THE QPE INDICATES SEVERAL
INCHES OF RAIN HAVE ALREADY FALLEN ALONG THE BORDER OF TN/AL WITH
LOCAL MAXIMA ESTIMATED AT OVER 6 INCHES IN THE PAST 6 HOURS. THUS
FAR...ONLY THE 16Z HRRR APPEARS TO BE HANDLING THE ONGOING
CONVECTION WELL. THE HRRR EXPECTS A WIDESPREAD 1 TO 2 INCHES IN
THE NEXT 6 HOURS WITH ISOLATED POCKETS OF 2 TO 3 INCHES WHICH WILL
BE ON TOP OF ALREADY VERY WET SOILS.
RUBIN-OSTER
ATTN...WFO...BMX...FFC...HUN...MEG...MRX...OHX...
ATTN...RFC...LMRFC...OHRFC...SERFC...
LAT...LON 36018662 35828502 35218427 34528438 34508551
34518688 34298810 34788879 35618844
Last Updated: 151 PM EDT MON AUG 18 2014
|