996
FXUS64 KMEG 082253 AAA
AFDMEG
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MEMPHIS TN
453 PM CST SUN NOV 8 2009
DISCUSSION
/ISSUED 308 PM CST SUN NOV 8 2009/
AN UPPER LEVEL RIDGE OF HIGH PRESSURE REMAINS POSITIONED OVER THE
MID SOUTH AND NORTHERN GULF COAST STATES THIS AFTERNOON. THIS
FEATURE SHOULD KEEP DRY WEATHER AND ABOVE AVERAGE TEMPERATURES IN
THE FORECAST INTO MONDAY AFTERNOON. MID AND HIGH LEVEL CLOUDS WILL
BE ON THE INCREASE TONIGHT INTO MONDAY AS MOISTURE ALOFT CONTINUES
TO INCREASE FROM THE SOUTH.
THE BIG WEATHER STORY FOR THE FIRST HALF OF THE WEEK WILL BE THE
EVENTUAL TRACK AND IMPACTS FROM HURRICANE IDA. IDA HAS JUST
RECENTLY ENTERED THE SOUTHEAST GULF OF MEXICO AND CONTINUES TO
MOVE NORTHWESTWARD. IDA IS NOW A CATEGORY 2 HURRICANE WITH
SUSTAINED WINDS OF AROUND 100 MPH. SOME ADDITIONAL STRENGTHENING
IS POSSIBLE OVERNIGHT BEFORE A WEAKENING TREND BEGINS AS MID AND
UPPER LEVEL SOUTHWESTERLY SHEAR STRENGTHENS AND THE HURRICANE
MOVES INTO THE COOLER WATERS OF THE CENTRAL AND NORTHERN GULF OF
MEXICO.
A SERIES OF UPPER LEVEL LOW PRESSURE SYSTEMS...ONE OVER THE WESTERN
GULF OF MEXICO AND A SECOND OVER THE BIG BEND OF TEXAS WILL
CONTINUE TO ERODE THE WESTERN PERIPHERY OF THE UPPER RIDGE AS THEY
LIFT OFF TO THE NORTHEAST AND NORTH. THIS SHOULD HELP TO STEER
HURRICANE IDA INCREASINGLY NORTHWARD AND AT A QUICKER PACE ON
MONDAY AND MONDAY NIGHT. IDA SHOULD WEAKEN SOME MONDAY AND MONDAY
NIGHT AS IT INTERACTS WITH THE SHORTWAVE ALOFT APPROACHING FROM
THE WEST AND BEGINS AN EXTRATROPICAL TRANSITION. ALTHOUGH IDA WILL WEAKEN
SOME...IT NOW APPEARS AS THOUGH THE SYSTEM COULD STILL MAINTAIN
HURRICANE FORCE WINDS AS IT REACHES THE NORTH CENTRAL GULF COAST
BY EARLY TUESDAY MORNING.
THERE STILL REMAINS SUFFICIENT SPREAD AMONG THE FORECAST MODELS
THIS AFTERNOON WITH RESPECT TO HOW FAR WEST AND NORTH THE TROPICAL
CYCLONE WILL MOVE. THIS HAS A RATHER LARGE IMPACT WITH RESPECT TO
RAIN CHANCES ACROSS THE MID SOUTH FOR MONDAY NIGHT INTO TUESDAY.
AT THIS POINT...IT APPEARS THAT IDA (OR ITS REMNANTS) SHOULD
REMAIN FAR ENOUGH SOUTHEAST OF THE AREA TO KEEP THE MAJORITY OF
THE RAIN CONFINED MAINLY SOUTHEAST OF INTERSTATE 40. THE GREATEST
RAIN POTENTIAL SHOULD REMAIN ACROSS NORTHEAST MISSISSIPPI MONDAY
NIGHT INTO TUESDAY MORNING...WHERE LIKELY POPS HAVE BEEN
MAINTAINED. ALSO HAVE ADDED THE POTENTIAL FOR MODERATE RAIN AT
TIMES OVER THESE AREAS. LIGHTER RAINS AND DECREASING CHANCES CAN
BE EXPECTED FURTHER NORTH AND WEST. HAVE KEPT A SLIGHT CHANCE
MENTION OF LIGHT RAIN SHOWERS OVER MUCH OF THE REGION ON TUESDAY
TO ACCOUNT FOR THE PASSAGE OF THE UPPER TROUGH AND COLD FRONT FROM
THE WEST...BUT THINK THE MAJORITY OF DEEPER MOISTURE WILL BE
SWEPT EAST WITH THE REMNANTS OF IDA.
GUSTY NORTHEAST TO NORTH WINDS CAN ALSO BE EXPECTED ACROSS THE
REGION MONDAY EVENING THROUGH TUESDAY NIGHT AS THE PRESSURE
GRADIENT STRENGTHENS BETWEEN CANADIAN SURFACE HIGH PRESSURE
BUILDING IN FROM THE NORTH AND TROPICAL CYCLONE IDA. THIS WILL
NEED TO BE MONITORED OVER THE NEXT COUPLE OF FORECAST SHIFTS.
ANY RAIN ASSOCIATED WITH IDA AND THE UPPER TROUGH WILL BE EAST OF
THE AREA BY TUESDAY NIGHT WITH CANADIAN HIGH PRESSURE BUILDING
SOUTHWARD OVER THE REGION. IN ADDITION...MID AND UPPER LEVEL
RIDGING WILL BUILD THROUGH THE MIDDLE TO END OF THIS WEEK. THIS
WILL KEEP DRY AND SEASONABLY COOL WEATHER IN PLACE FOR WEDNESDAY
THROUGH THURSDAY...WITH A GRADUAL WARMING TREND EXPECTED FOR
FRIDAY AND INTO NEXT WEEKEND. ANOTHER UPPER TROUGH WILL SLOWLY
APPROACH FROM THE WEST NEXT WEEKEND WITH INCREASING MOISTURE...RAIN
CHANCES...AND ABOVE AVERAGE TEMPERATURES.
JLH
AVIATION
00Z TAF CYCLE (09/00Z-10/00Z)
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD WITH MID AND HIGH
LEVEL CLOUDS SPREADING ACROSS THE REGION FROM THE SOUTH. SURFACE
HIGH PRESSURE WILL STRETCH FROM OFF THE ATLANTIC COAST WESTWARD
ACROSS THE MIDSOUTH. HURRICANE IDA WILL MOVE INTO THE NORTHERN
GULF LATE IN THE FORECAST PERIOD. WINDS WILL TURN MORE TO THE EAST
MONDAY BUT WILL REMAIN 8 KTS OR LESS.
JCL
PRELIMINARY POINT TEMPS/POPS
MEM 56 71 55 69 / 0 10 20 20
MKL 51 71 51 67 / 0 10 20 20
JBR 52 71 51 67 / 0 10 10 20
TUP 53 69 55 66 / 0 20 60 40
MEG WATCHES/WARNINGS/ADVISORIES
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
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