000
FXUS63 KPAH 020021
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
620 PM CST SUN MAR 1 2015

.UPDATE...
ISSUED AS 620 PM CST SUN MAR 1 2015

UPDATED AVIATION SECTION ONLY.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 311 PM CST SUN MAR 1 2015

NO REST FOR THE WEARY IN THE SHORT TERM. MULTIPLE PRECIPITATION
EVENTS ON THE AGENDA WITH A POTPOURRI OF WEATHER TYPES...INCLUDING
FREEZING RAIN...FREEZING DRIZZLE...RAIN...SLEET...SNOW...AND
THUNDER...JUST TO NAME A FEW.

A SURFACE TROUGH IN THE VICINITY COMBINED WITH DEEP LAYER MOISTURE
PRODUCING LIGHT OVERRUNNING PRECIPITATION IN THE FORM OF RAIN OR
DRIZZLE WILL CONTINUE OVER MOST OF THE CWA THIS AFTERNOON. THE
EXCEPTION IS NORTH AND WEST OF A LINE FROM FAIRFIELD TO
PINCKNEYVILLE ILLINOIS WHERE TEMPERATURES HOVERING AT OR JUST BELOW
FREEZING COMBINED WITH LIGHT DRIZZLE OR SLEET ARE PRODUCING SLIPPERY
CONDITIONS. A FEW ACCIDENTS HAVE BEEN REPORTED IN THESE AREAS.

AS THE TROUGH BEGINS TO MOVE OFF TO THE EAST TONIGHT...PRECIPITATION
SHOULD BEGIN TO DIMINISH FROM THE NORTHWEST STARTING LATE THIS
AFTERNOON. AFTER MIDNIGHT SMALL PRECIPITATION CHANCES IN THE FORM OF
FREEZING DRIZZLE OR SLEET ARE EXPECTED TO LINGER GENERALLY SOUTH OF
A LINE FROM GREENVILLE TO BENTON KENTUCKY TO CHARLESTON TO NEW
MADRID MISSOURI. ANY ICE ACCUMULATION SHOULD BE MINIMAL AT BEST...
AND HAVING COORDINATED WITH SURROUNDING OFFICES...WILL HANDLE WITH A
SPECIAL WEATHER STATEMENT VERSUS A WINTER WEATHER ADVISORY AT THIS
TIME.

MONDAY IS CURRENTLY FORECAST TO BE DRY AS HIGH PRESSURE MOVES ACROSS
THE AREA...BUT MONDAY NIGHT PRECIPITATION CHANCES MAKE THEIR WAY
BACK INTO OUR CWA AS A WARM FRONT ASSOCIATED WITH A SYSTEM OVER THE
PLAINS APPROACHES AND LIFTS NORTHEAST ACROSS OUR AREA. BEFORE THE
WARM FRONTAL PASSAGE...PRECIPITATION MAY FALL IN THE FORM OF
FREEZING RAIN OR SLEET OVER THE NORTHWEST HALF OF THE CWA...THEN AS
TEMPERATURES RISE OVERNIGHT...CHANGE OVER TO ALL RAIN WITH THE
EXCEPTION OF THE FAR NORTHWEST SECTIONS WHERE FREEZING RAIN AND/OR
SLEET MAY CONTINUE.

IN THE WAKE OF THE WARM FRONTAL PASSAGE...THERE WILL BE A RAPID AND
WELCOMED WARMUP ON TUESDAY AND WITH IT INCREASED CHANCES FOR RAIN
SHOWERS...LOCALLY HEAVY RAINFALL...AND SCATTERED THUNDERSTORMS WITH
THE APPROACH OF A STRONG COLD FRONT.

THE COLD FRONT WILL CROSS THE REGION TUESDAY NIGHT. MODELS ARE STILL
CRANKING OUT IMPRESSIVE AMOUNTS OF QPF WITH THE FRONTAL PASSAGE.
LATE TUESDAY NIGHT STRONG COLD AIR ADVECTION BEHIND THE FRONT MAY
CHANGE PRECIPITATION OVER TO FREEZING OR FROZEN OVER THE NORTHWEST
HALF OF OUR CWA...WITH ALL RAIN AND SCATTERED THUNDERSTORMS OVER THE
SOUTHEAST HALF.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 311 PM CST SUN MAR 1 2015

AT THE BEGINNING OF THE EXTENDED FORECAST PERIOD (DAYTIME
WEDNESDAY), THE POSITIVE TILTED AND SHEARED TROUGH THAT EXTENDS FROM
THE UPPER MIDWEST TO THE SOUTHWEST U.S. WORKS SOUTHEAST. THE BASE OF
THIS TROUGH ARCS A LITTLE FASTER, MAKING THE TROUGH SLIGHTLY
AMPLIFIED AND IMPRESSING A LOW AMPLITUDE BAROCLINIC "LEAF" ZONE OF
ENHANCED LIFT TOWARD THE WFO PAH FORECAST AREA.  AT THE LOW LEVELS,
THE COLD CANADIAN AIR MASS CONTINUES TO MOVE UNABATED OVER THE
REGION. THIS WILL SET UP A NARROW, BUT DISTINCT OVER-RUNNING REGIME
OF PRECIPITATION AS THIS TROUGH MOVES TOWARD THE AREA DURING THE DAY
WEDNESDAY AND WEDNESDAY NIGHT. GIVEN THE CHANNELED NATURE OF THE
LIFT PARALLET WITH THE UPPER FLOW, THE FAVORABLE ZONE FOR ISENTROPIC
LIFT, MAXIMUM ICE CRYSTAL GROWTH, PERSISTENT MOISTURE ADVECTION,
ETC...WILL BE NARROW AS WELL.

AT THIS POINT, IT IS TOO EARLY TO TELL IF THIS WILL MEET WINTER
WEATHER ADVISORY CRITIERIA LEVEL, BUT IT WILL REQUIRE MONITORING AS
THE SMALLER SCALE UPPER LEVEL FEATURES BECOME REOLVED BETTER IN THE
HIGHER RESOLUTION NUMERICAL MODELS.

OTHERWISE, DRY CONDITIONS WILL DOMINATE FOR THE REST OF THE EXTENDED
FORECAST PERIOD, WITH A SLOW, BUT GRADUAL RISE IN TEMPERATURES
BEGINNING ON THURSDAY.

IT IS IMPRESSIVE TO NOTE THAT THE DETERMINISTIC GFS GUIDANCE DURING
THE MIDDLE OF LAST WEEK ACTUALLY PICKED UP ON THE ORIENTATION AND
STRENGTH OF THE MID-WEEK COLD AIR SURGE BEING DEPICTED IN THE
CURRENT RANGE OF NUMERICAL MODEL SUITE. THE LATEST CHANGES IN THE
CONSTRUCTION OF THE PHYSICS AND RESOLUTION OF THE GFS APPEAR TO BE
SHOWING BETTER IMPROVEMENT.

&&

.AVIATION...
ISSUED AT 620 PM CST SUN MAR 1 2015

THE MOST PESSIMISTIC CONDITIONS WILL BE ALONG THE TN STATE LINE
TONIGHT. DRIER AIR WILL CONTINUE TO FILTER INTO THE PAH FORECAST
AREA FROM THE NW. AT THE TAF SITES...IT WILL TAKE A WHILE FOR
MVFR...AND IN SOME CASES IFR...CIGS TO RISE OVERNIGHT. VSBYS COULD
DIP INTO THE 6SM RANGE FROM TIME TO TIME DUE TO AVAILABLE MOISTURE
FROM SNOWMELT. EXPECT VFR CONDITIONS BY DAYBREAK...WITH GENERALLY
LIGHT SFC WINDS VEERING TO A MORE ERLY DIRECTION.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

$$

SHORT TERM...JP
LONG TERM/AVIATION/FIRE WX...KES