FXUS64 KMEG 080549
AFDMEG
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1149 PM CST MON DEC 7 2009
.UPDATE...
UPDATED FOR O6Z TAF DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 830 PM CST MON DEC 7 2009/
DISCUSSION...
THINGS LOOK ON TRACK WITH TEMPERATURES AND WIND OVERNIGHT. RADAR
SHOWS PRECIPITATION MAY BE A LITTLE SLOWER IN MOVING INTO AREA
THAN FORECASTED. HOWEVER...GRIDS AND TEXT STILL HANDLE THE
SITUATION OKAY.
SO EXPECT RAIN TO MOVE IN OR DEVELOP IN SOUTHWESTERN PART OF
COUNTY WARNING AREA BEFORE MIDNIGHT AND THEN MOVE OVER MOST OF
MID-SOUTH BY MORNING.
SINCE THINGS ARE ON TRACK...NO UPDATE IS PLANNED. TLSJR
PREV DISCUSSION... /ISSUED 257 PM CST MON DEC 7 2009/
DISCUSSION...
KEY CHALLENGES IN THIS FORECAST PACKAGE ARE A HEAVY RAIN EVENT
LATE TONIGHT AND TUESDAY AND A POTENTIAL WINTRY MIX ACROSS
NORTHERN PORTIONS OF THE MID SOUTH FRIDAY NIGHT AND EARLY
SATURDAY. WILL ALSO HAVE TO MONITOR POSSIBLE SEVERE WEATHER ACROSS
NORTH CENTRAL MISSISSIPPI TUESDAY AFTERNOON AND EVENING.
TONIGHT THROUGH TUESDAY NIGHT...A POWERFUL H5 UPPER LEVEL TROUGH
WILL MOVE FROM THE FOUR CORNERS REGION INTO THE SOUTHERN PLAINS
STATES ON TUESDAY. GULF MOISTURE WILL SPREAD INTO THE MID SOUTH
OVERNIGHT AND CONTINUE ON TUESDAY. FORECAST MODELS INDICATE
RAINFALL AMOUNTS OF 1.5 TO 2.5 INCHES. WILL UPDATE THE FLOOD
POTENTIAL AND HAZARDOUS WEATHER OUTLOOKS. THE MID SHIFT MAY NEED
TO ISSUE A FLASH FLOOD WATCH.
THE 12Z GFS AND ECMWF PUSH A SURFACE WARM FRONT INTO WESTERN TN ON
TUESDAY WHICH WOULD OPEN THE DOOR FOR SEVERE WEATHER DURING THE
AFTERNOON AND EVENING HOURS. PREFER THE 12Z NAM SOLUTION WITH ITS
FINER RESOLUTION NEAR AND ABOVE THE BOUNDARY LAYER. EXPECT THE LOW
LEVEL COLD LAYER TO HOLD IN FOR MUCH OF THE DAY. NORTH CENTRAL MS
MAY EXPERIENCE THREE TO SIX HOURS IN THE WARM SECTOR...THEREFORE WILL
HAVE TO MONITOR THE SITUATION.
WEDNESDAY AND THURSDAY...FAST ZONAL FLOW ALOFT AND SURFACE HIGH
PRESSURE WILL PROVIDE THE REGION WITH DRY AND SEASONABLY COLD
WEATHER.
FRIDAY THROUGH SATURDAY...12Z MODEL GUIDANCE BRINGS SOUTHWESTERLY
FLOW ALOFT WHICH ALLOWS GULF MOISTURE TO ADVECT INTO THE MID
SOUTH. THE CURRENT RUN IS NOT AS COLD AS ITS IMMEDIATE
PREDECESSOR...THEREFORE MOVED THE CHANCE OF A WINTRY MIX TO THE
NORTHERN THIRD OF THE FORECAST AREA.
SUNDAY AND MONDAY...A FAST ZONAL FLOW RETURNS EARLY NEXT WEEK.
HARD TO TIME DISTURBANCES IN THIS TYPE OF PATTERN SIX OR SEVEN
DAYS OUT. DECIDED TO INSERT LOW POPS TO REFLECT LOW CONFIDENCE.
OKULSKI
&&
.AVIATION...
06Z TAF CYCLE
LIFR CIGS HAVE ALREADY REACHED KTUP AS LOW LEVEL MOISTURE CONTINUES
TO STREAM INTO THE AREA FROM THE SOUTHWEST. IFR CIGS ARE SEEN
ELSEWHERE WITH THE EXCEPTION OF KJBR. BELIEVE -RA WILL BEGIN AT
ALL SITES BY 11Z TO 12Z IF NOT SOONER. PLACED TEMPO GROUPS TO
ACCOUNT FOR PERIODS OF HEAVY RAIN FROM 18Z TO 22Z. KEPT VSBYS NO
LOWER THAN IFR DURING THIS TIME FRAME BUT BELIEVE VSBYS COULD
BRIEFLY TOUCH LIFR LEVELS DURING HEAVIEST PRECIPITATION. ALSO MENTIONED
VCTS AT KTUP AFTER 22Z WITH BETTER INSTABILITY. WINDS WILL VEER
AROUND TO THE SOUTH DURING THE AFTERNOON HOURS AND INCREASE AS THE
SURFACE PRESSURE GRADIENT TIGHTENS.
CCD
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 43 59 44 47 / 90 100 60 10
MKL 39 57 43 47 / 90 100 70 10
JBR 35 48 38 40 / 90 100 60 10
TUP 43 62 48 52 / 90 100 100 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
