MESOSCALE PRECIPITATION DISCUSSION 0103
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
500 PM EDT WED APR 05 2017

AREAS AFFECTED...FL PANHANDLE...FAR SOUTHERN GA

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

VALID 052059Z - 060100Z

SUMMARY...A TRAINING AXIS OF SHOWERS AND THUNDERSTORMS...WITH
LOCALLY VERY HEAVY RAINFALL TOTALS IS EXPECTED THROUGH EARLY THIS
EVENING. SOME FLASH FLOODING WILL BE POSSIBLE AS A RESULT.

DISCUSSION...A ROBUST SOUTHWEST LOW LEVEL JET OF 40 TO 45 KTS
CONTINUES TO TRANSPORT A VERY MOIST AND UNSTABLE AIRMASS NORTHEAST
OUT OF THE GULF OF MEXICO AND INTO A CONVECTIVELY REINFORCED
OUTFLOW BOUNDARY OVER SOUTH-CENTRAL GA. THIS BOUNDARY IS BECOMING
BETTER DEFINED FARTHER SOUTHWEST INTO THE WESTERN FL PANHANDLE AS
WELL. A PLUME OF HIGHER PWATS...1.6 TO 1.8 INCHES...IS SEEN IN THE
CIRA-LPW PRODUCT AND ORIENTED SW/NE FROM THE CURRENT AXIS OF
CONVECTION AND THEN OFFSHORE INTO THE GULF OF MEXICO. THIS IS WELL
ALIGNED WITH THE LOW LEVEL JET AND THIS CONTINUES TO HELP SUSTAIN
THE BACKBUILDING/REPEATING AXIS OF CONVECTION OCCURRING OVER
SOUTH-CENTRAL GA AND FARTHER SOUTHWEST INTO THE FL PANHANDLE.

GIVEN MODERATE UPSTREAM INSTABILITY...WHICH IS UPWARDS OF 1500 TO
2000 J/KG OF MLCAPE...AND THE DEEP LAYER MOISTURE
TRANSPORT...ADDITIONAL CONVECTION IS EXPECTED OVER THE NEXT FEW
HOURS WITH STRONG CONCERNS FOR BACKBUILDING AND TRAINING. THE
OVERALL CONVECTIVE AXIS WILL LIKELY TEND TO SLOWLY SAG OR BOW
SOUTHEAST GIVEN THE STRENGTHENING OF A LOW LEVEL COLD POOL OVER
SOUTH-CENTRAL GA...BUT THIS REINFORCED SURFACE BOUNDARY WILL ONLY
ACT TO HELP INITIATE CONVECTION FARTHER SOUTH.

THE 12Z ARW AND RECENT RUNS OF THE HRRR-EXP WERE HIGHLIGHTING THIS
CONVECTIVE TRAINING POTENTIAL. THE RAINFALL RATES ARE LIKELY TO
REACH 2 TO 2.5 INCHES/HR GIVEN THE HIGHER PWATS AND SURFACE
DEWPOINTS EXCEEDING 70 DEGREES. STORM TOTALS AMOUNTS OF 4 TO 6
INCHES WILL BE POSSIBLE AT LEAST LOCALLY. EXPECT FLASH FLOODING TO
BE A CONCERN THROUGH EARLY EVENING AS A RESULT.

ORRISON

ATTN...WFO...CHS...FFC...JAX...TAE...

ATTN...RFC...SERFC...

LAT...LON   32228194 32218104 31448114 31008183 30708291
            30398407 30198572 30508628 30928573 31448425