821
AWUS01 KWNH 090913
FFGMPD
MSZ000-LAZ000-ARZ000-091501-
MESOSCALE PRECIPITATION DISCUSSION 0007
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
412 AM EST FRI JAN 09 2026
AREAS AFFECTED...CENTRAL MISSISSIPPI...EASTERN AND NORTHEASTERN
LOUISIANA...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 090911Z - 091501Z
SUMMARY...FLATTENING STEERING FLOW TO SUPPORT SEGMENTED TRAINING
CORRIDORS ACROSS THE LOWER MISSISSIPPI RIVER VALLEY.
STRENGTHENING CONVERGENCE AND MODESTLY UNSTABLE AND SEASONABLY
MOIST AIR SHOULD SUPPORT RAIN RATES TO 1.75" AND LOCALIZED STREAKS
OF 2-4" IN 1-3HRS. SUGGESTING LOCALIZED FLASH FLOODING IS
POSSIBLE THIS MORNING TO START A LONGER DAY OF REPEAT
THUNDERSTORMS.
DISCUSSION...GOES-E WV SUITE SHOWS MATURE/DECAYING SHORTWAVE
RAPIDLY ELONGATING AND SLIDING NORTHEAST THROUGH THE CENTRAL GREAT
LAKES WITH A WELL DEFINED BROADLY ANTICYCLONICALLY CURVED
SUBTROPICAL JET STREAK ACROSS TEXAS THROUGH KY/TN WITH A STRONGER
BASE OF THE NORTHERN STREAM SYNOPTIC TROUGH WELL UPSTREAM EMERGING
INTO THE SOUTHERN HIGH PLAINS. THE STRONG FLOW AND UPPER-LEVEL
DYNAMIC SUPPORT HAS RESULTED IN WELL ABOVE NORMAL MOISTURE FLUX
ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE GREAT LAKES; CIRA LPW
DENOTES CORE OF HIGHER MOISTURE/THETA-E AIR OVER THE WEST GULF IS
ADVANCING INTO THE ENTRANCE OF THE EASTERN US ATMOSPHERIC RIVER
STREAM. SURFACE TO 850MB VALUES ARE NEARING 1" AND IS NOTED WITH
SURFACE TDS IN THE UPPER 60S TO EVEN SPOTS OF 70 ACROSS THE LOWER
MS VALLEY.
THE OVERALL ORIENTATION OF THE UPPER-LEVEL FLOW IS SUPPORTING A
PRE-FRONTAL CONFLUENCE ZONE ACROSS E LA AT THIS TIME, PROVIDING
SUFFICIENT DEEP LAYER CONVERGENCE TO TAP THE WEAKLY UNSTABLE AIR.
MLCAPES ARE ANALYZED FROM 500-1000 J/KG THROUGH THE SABINE RIVER
VALLEY INTO THE DELTA REGION OF SE AR AND W MS. FLUX CONVERGENCE
OF 30-35KTS AT ABOUT 30 DEGREES OF CONVERGENCE OVERLAPS WITH THE
CORE OF THE MOISTURE AXIS WITH TPW NEAR 1.7". AS SUCH, RADAR
DENOTES A FEW CLUSTERS OF THUNDERSTORMS DEVELOPING ACROSS NE LA AS
WELL AS FURTHER NORTH ACROSS NE LA INTO W MS, THE LATTER DEEPER
INTO THE MORE IDEAL UNIDIRECTIONAL FLOW AND MAY SUPPORT SOME
TRAINING ELEMENTS AS THE OVERALL CONVECTIVE DEVELOPMENT EXPANDS
AND INTENSIFIES OVER THE NEXT FEW HOURS. THE STRONG MOISTURE FLUX
CONVERGENCE MAINLY BELOW 700MB WILL SUPPORT RATES OF 1.75"; AND
WHILE THE FORWARD SPEEDS WILL LIMIT ANY SPECIFIC CORE, THE
UPSTREAM DIVERGENCE ALOFT AND STRENGTH OF LOW LEVEL FLOW
CONVERGENCE WILL SUPPORT BACK-BUILDING AND REDEVELOPMENT UPSTREAM
THROUGH CENTRAL LA THROUGHOUT THE MORNING.
LOCALIZED STORM OUTFLOWS MAY BE THE KEY TO ESTABLISHING THE MOST
IDEAL TRAINING PROFILES, BUT EVEN 1-2 HOURS OF THESE RATES COULD
SUPPORT 2-3" TOTALS AND LOCALLY HIGHER VALUES TO 4" WOULD THEN
BEGIN TO EXCEED THE HIGH (3"/3HRS) FFG VALUES IN THE AREA.
00Z/06Z HREF PROBABILITY OF 3"/3HRS PEAK AROUND 30% IN SW TO
CENTRAL MS. STILL EVEN WITH DORMANT GROUND CONDITIONS, THESE
RATES/TOTALS WILL HAVE THE GREATEST POTENTIAL FOR FLASH
FLOODING/RAPID INUNDATION CONDITIONS WHERE INTERSECTING URBAN
CENTERS. IN ANY CASE, THESE CELLS WILL SATURATE THE UPPER SOIL
PROFILES PRIOR TO FURTHER CONVECTIVE ACTIVITY EXPECTED THROUGHOUT
THE DAY AND EVENING. AS SUCH, FLASH FLOODING IS ONLY CONSIDERED
POSSIBLE AND LIMITED TO WIDELY SCATTERED IN COVERAGE THROUGH THE
EARLY MORNING PERIOD.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...JAN...LCH...LIX...MEG...SHV...
ATTN...RFC...ALR...ORN...NWC...
LAT...LON 34138908 34058839 33498829 32868864 32288915
31568980 30709050 30919161 30929254 31469279
32169248 33289103 33719020
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