Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 090521
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1121 PM CST MON FEB 8 2016

.DISCUSSION...
UPDATED FOR 06Z AVIATION DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 613 PM CST MON FEB 8 2016/

UPDATE...

UPDATED TO CLEAN UP EVENING WORDING AND REMOVE WIND ADVISORY.

DISCUSSION...

A STRONG UPPER LEVEL LOW PRESSURE SYSTEM OVER THE SOUTHERN GREAT
LAKES WILL REMAIN IN PLACE TONIGHT WITH CYCLONIC FLOW ALOFT
IMPACTING THE MID SOUTH. ANOTHER SHORTWAVE EMBEDDED WITHIN THIS
FLOW WILL IMPACT THE AREA THIS EVENING AND BRING ANOTHER ROUND OF
SCATTERED FLURRIES AND SNOW SHOWERS...ESPECIALLY ACROSS NORTHWEST
TENNESSEE WHERE A MINOR DUSTING CANNOT BE RULED OUT THIS EVENING.

THE CURRENT FORECAST LOOKS GOOD AND ONLY UPDATING TO CLEAN UP PRE
FIRST PERIOD WORDING AND REMOVE THE WIND ADVISORY. UPDATES TO
PRODUCTS WILL BE SENT SHORTLY.

JLH

&&

PREV DISCUSSION... /ISSUED 310 PM CST MON FEB 8 2016/

DISCUSSION...
MIDAFTERNOON GOES WATER VAPOR IMAGERY SHOWED A DEEP LONGWAVE UPPER
LEVEL TROF COVERING THE EAST/CENTRAL THIRD OF CONTIGUOUS U.S...
CENTERED OVER LAKE MICHIGAN. NORTH/NORTHWEST UPPER LEVEL FLOW
PREVAILED OVER THE MIDSOUTH...WITH TRAJECTORIES ORIGINATING FROM
THE BEAUFORT SEA...NORTH OF ALASKA. AT THE SURFACE... GUSTY
NORTHWEST WINDS PREVAILED NEAR WIND ADVISORY CRITERIA OVER
NORTHEAST AR...AND BELOW ADVISORY CRITERIA ELSEWHERE. NEAR DRY
ADIABATIC LOW LEVEL LAPSE RATES WERE AIDING IN THE DEVELOPMENT OF
SCATTERED SNOW SHOWERS...SOME OF WHICH WAS EVAPORATING IN THE DRY
SUB CLOUD LAYER BEFORE REACHING THE GROUND.

FOR TONIGHT...EXPECT WINDS TO DIURNALLY WEAKEN BUT NOT DIMINISH IN
THE WELL MIXED ARCTIC AIRMASS. WITH THE LOSS OF MODEST SURFACE
HEATING...LAPSE RATES SHOULD WEAKEN SUFFICIENTLY FOR A GRADUAL REDUCTION
IN SNOW SHOWER COVERAGE. SHOW SHOWERS WILL LIKELY PERSIST LONGEST
NEAR THE TN RIVER...WHERE THE NAM MODEL DEPICTS 280K SATURATION
PRESSURE DEFICITS LESS THAN 10 MB. BY 06Z...THE NAM MODEL DEPICTED
NEUTRAL OR NEGATIVE ISENTROPIC NEAR THE TN RIVER AFTER
06Z/MIDNIGHT CST. AT THIS TIME...LITTLE TO NO ACCUMULATIONS ARE
ANTICIPATED...BUT CAN/T RULE OUT A LOCALIZED 1 INCH ABOUT SHOULD A
MORE PERSISTENT BAND SET UP OVER NORTHWEST TN THIS EVENING.

THE COMBINATION OF THE UPPER TROF LIFTING EAST AND COLDER LOW
LEVEL TEMPS WILL CONTINUE TO WEAKEN LOW LEVEL LAPSE RATES TUESDAY...
LIMITING PRECIPITATION CHANCES TO AREAS NEAR THE TN RIVER.

COLD TEMPS APPEAR IN ORDER THE FOR THE REMAINDER OF THE WEEK.
GFS AND ECMWF DEPICT AN ADDITIONAL ARCTIC COLD FRONT ARRIVING
INTO THE MIDSOUTH FRIDAY EVENING...UNDER PERSISTENT NORTHWEST FLOW
ALOFT. THE ECMWF REMAINS MORE AMPLIFIED WITH THE UPPER PATTERN...AND
TAKES A MORE DIRECT SHOT AT THE MIDSOUTH WITH THE ARCTIC AIR. THE
LESS AMPLIFIED GFS QUICKLY LIFTS THE ARCTIC HIGH TO THE CAROLINAS
BY SUNDAY...WITH SOUTHERLY LOW LEVEL RETURN FLOW AND EVENTUAL
RAIN/SHOW EVENT WITH A PACIFIC COLD FRONTAL PASSAGE SUNDAY NIGHT.
THE ECMWF KEEPS THE ARCTIC AIR LOCKED OVER THE MIDSOUTH ON
SUNDAY...FOLLOWED BY A SNOW EVENT ASSOCIATED WITH A RELATIVELY
STRONG SHORTWAVE DROPPING INTO OHIO VALLEY. THE MODEL BLENDED
SOLUTIONS HAVE TRENDED COLDER FOR NEXT WEEKEND...AND APPEAR ON THE
CORRECT PATH...GIVEN THE STRENGTH OF FRIDAY NIGHT/S ARCTIC COLD
FRONT.

PWB

&&

.AVIATION...

06Z TAF SET

VFR WEATHER TO CONTINUE THROUGH THE PERIOD...WITH GREATER
CONFIDENCE THAT CIGS WILL REMAIN VFR AT MKL DURING MORNING PERIOD
OF LIGHT SNOW SHOWERS. THE BIGGEST CONCERN WILL REMAIN GUSTY
NORTHWEST WINDS...WITH THE HIGHEST GUSTS AT JBR AND MEM. WINDS
WILL DIMINISH LATE IN THE PERIOD...WITH CLEARING SKIES.

JAB

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$


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