Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 222239
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
539 PM CDT Tue Jul 22 2014

.UPDATE...
Issued at 535 PM CDT TUE JUL 22 2014

Updated Aviation Section for 00Z TAF Issuance.

&&

.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 256 PM CDT TUE JUL 22 2014

GOES SOUNDER PRECIPITABLE WATER CONTINUES TO SHOW A VERY SUBTLE, BUT
CONTINUAL MOISTENING OF THE ATMOSPHERIC LAYER OVER THE WFO PAH
FORECAST AREA. AT THIS TIME, MOST OF THE CONTRIBUTION IS COMING FROM
THE BOUNDARY LAYER AND THE MIDDLE LEVELS OF THE ATMOSPHERE IN
ADVANCE OF THE SLOWLY APPROACHING SHORTWAVE/SURFACE FRONT FROM THE
NORTHWEST.

NAM SOUNDINGS SUGGEST THAT MOST OF THE INSTABILITY FOR CONVECTIVE
DEVELOPMENT WILL BE ELEVATED ALONG OR BEHIND THE FRONT WEDNESDAY,
WITH ONLY A NARROW TIME PERIOD WHERE LAPSE RATES, MOISTURE, FRONTAL
CONVERGENCE, AND INSTABILITY WILL BE FAVORABLE FOR THUNDERSTORM
DEVELOPMENT. AT THIS TIME, THE BEST WINDOW FOR CONVECTION LOOKS TO
BE 16-18Z OVER SOUTHEAST MO (MAINLY ALONG AND NORTH OF KPOF-KCGI
LINE), SPREADING ACROSS EXTREME SOUTHERN ILLINOIS, AND NEAR
NORTHWEST KENTUCKY (ALONG AND SOUTH OF A KEHR-KOWB LINE) BETWEEN
20-22Z.

FOR NOW, KEPT THE TREND OF SCATTERED COVERAGE IN POPS FOR
WEDNESDAY/WEDNESDAY NIGHT AS CAPPING ALOFT CONTINUES TO BE MORE OF
AN ISSUE TO LIMIT MORE ROBUST THUNDERSTORM DEVELOPMENT. SHOWER
DEVELOPMENT AND COVERAGE MAY BE MORE EFFECTIVE ACROSS THE WFO PAH
AREA, MAINLY DUE TO SPREADING OF MID-DECK CLOUD COVER AND ELEVATED
SHOWERS.

HEAT INDEX VALUES AHEAD OF THE FRONT WILL ONCE AGAIN APPROACH THE
95-100 DEGREE RANGE WEDNESDAY, MAINLY ACROSS WEST KENTUCKY.

DRIER AND COOLER CONDITIONS WILL RETURN ON THURSDAY.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 256 PM CDT TUE JUL 22 2014

MODEL PREFERENCE IS A BLEND OF THE 00Z ECMWF/GFS DETERMINISTIC
RUNS. HIGH PRESSURE OVER THE REGION THURSDAY NIGHT INTO FRIDAY
WILL MOVE OFF TO THE EAST BY 12Z SATURDAY. DRY WEATHER IS FORECAST
THURSDAY NIGHT INTO FRIDAY, FOLLOWED BY A SMALL CHANCE OF
CONVECTION OVER THE N/NE PART OF THE FORECAST AREA FRIDAY NIGHT, IN
RESPONSE TO A DEVELOPING WARM FRONT, AND SUBTLE MID LEVEL ENERGY
MOVING SE FROM THE UPPER MIDWEST. THE PATTERN WILL REMAIN
UNSETTLED THROUGH SUNDAY NIGHT. IT WILL BE QUITE WARM AND
UNSTABLE, WITH MINOR, HARD TO TIME, WEAK DISTURBANCES MOVING ESE
ACROSS THE AREA. WILL KEEP POPS IN CHECK GIVEN TIMING AND
PLACEMENT UNCERTAINTY.

IF THE MODELS KEEP WITH A SUNDAY AFTERNOON FROPA, WE MIGHT BE ABLE
TO RAISE POPS TO LIKELIES AT THAT TIME. IN ADDITION, IF THE FRONT
COMES INTO THE REGION IN THE AFTERNOON/EARLY EVENING, INSTABILITY
AND SHEAR VALUES SUGGEST SOME POTENTIAL FOR STRONG TO SEVERE
STORMS AS A STRONG H50 SHORT WAVES DIGS SOUTHEAST TOWARD THE
REGION. AGAIN, ALL DEPENDS ON TIMING. ANOTHER SHOT OF UNSEASONABLY
COOL CONDITIONS WILL FOLLOW EARLY NEXT WEEK. QUITE UNUSUAL FOR
LATE JULY.

&&

.AVIATION...
Issued at 535 PM CDT TUE JUL 22 2014

Some late night restrictions to vsby still possible with patchy
fog, mainly KCGI. Otherwise anticipate mainly VFR conditions, even
as front makes passage and light showers accompany said passage
along with wind shift tmrw by/before midday.

&&

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

$$





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