000
FXUS63 KPAH 182319
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
619 PM CDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 614 PM CDT SAT MAY 18 2013

UPDATE FOR 00Z AVIATION ONLY

&&

.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 306 PM CDT SAT MAY 18 2013

WITH WHATS LEFT OF AN UPPER LOW JUST TO THE NORTH AND EAST OF OUR
CWA...SCATTERED SHOWERS ARE POSSIBLE THIS AFTERNOON INTO THE EARLY
EVENING HOURS OVER THE EXTREME NORTHEAST SECTIONS OF OUR CWA.

MODELS CONTINUE TO INDICATE A SCENARIO TONIGHT THAT STILL MAKES NO
SENSE...BUT ALL MODELS ARE SHOWING (FOR THE MOST PART) THE SAME
THING. THEY SHOW A NW-SE ORIENTED SFC TROUGH DRAPED ACROSS OUR
CWA...AN H5 RIDGE BUILDING ACROSS THE AREA...AND A NW-SE ORIENTED
BAND OF LIGHT PRECIPITATION/QPF DEVELOPING ALONG AND/OR NEAR THE
BOUNDARY. NORMALLY A RIDGE BUILDING OVERHEAD TENDS TO
SQUASH/SUPPRESS ANY CHANCES FOR PRECIPITATION...BUT WITH THE
PRESENCE OF THE SFC TROUGH AND THE FACT THAT ALL MODELS CONTINUE TO
CRANK OUT A BAND OF LIGHT PRECIP...DECIDED TO KEEP SMALL POPS
OVERNIGHT INTO SUNDAY MORNING JUST IN CASE.

DONT EXPECT ANY PRECIP SUNDAY AFTERNOON AND EVENING...BUT WITH THE
RIDGE HAVING MOVED TO THE EAST OF THE AREA...IT WILL ALLOW PRECIP
CHANCES TO MAKE THEIR WAY BACK INTO THE FAR NORTHWESTERN AND WESTERN
SECTIONS OF OUR CWA LATE SUNDAY NIGHT AS THE NEXT WEATHER SYSTEM
APPROACHES FROM THE CENTRAL PLAINS. AS THE SYSTEM DRAWS NEARER TO
THE LOWER OHIO VALLEY...PRECIPITATION CHANCES WILL INCREASE MONDAY
INTO MONDAY NIGHT.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 306 PM CDT SAT MAY 18 2013

ECMWF...GFS AND GEM ALL SHOW A SURFACE LOW OVER THE UPPER MIDWEST
00Z WEDNESDAY...MOVING OVER THE LOWER GREAT LAKES REGION BY 00Z
THURSDAY.  GEM IS BIT FASTER THAN THE ECMWF WITH THE ASSOCIATED COLD
FRONT AND PRECIP TIMING.  GFS IS A LITTLE SLOWER THAN THE ECMWF AND
LESS DEFINED WITH PRECIP ENDING BECAUSE IT DEVELOPS A SECOND LOW
WHICH SLIDES ALONG THE FRONT LATE WEDNESDAY NIGHT INTO EARLY
THURSDAY.  THIS GFS SOLUTION IS NOT CONSISTENT WITH ITS PREVIOUS
RUN...AND PREFERRED TO LEAN TOWARD A ECMWF/GEM SOLUTION.  SHOWER AND
THUNDERSTORM CHANCES WILL INCREASE FROM WEST TO EAST ON TUESDAY WITH
THE APPROACH OF THE FRONT...WITH THE BEST CHANCES FOR MORE
SIGNIFICANT QPF TUESDAY NIGHT INTO WEDNESDAY.  WENT WITH LIKELY POPS
FOR THE ENTIRE PAH FORECAST AREA TUESDAY NIGHT...WITH LIKELY POPS
CONTINUING FOR OUR EASTERN THIRD OF COUNTIES ON WEDNESDAY.  MODELS
INDICATE THE FRONT WILL STALL OUT OVER OR JUST SOUTH OF THE FA FOR
WEDNESDAY NIGHT INTO THURSDAY NIGHT...SO KEPT SOME SLIGHT TO LOW
CHANCE POPS IN THE FORECAST FOR THESE TIME PERIODS.

GEM AND ECMWF BOTH SHOW HIGH PRESSURE BUILDING SOUTH OUT OF
CENTRAL/EASTERN CANADA FRIDAY AND INTO THE WEEKEND.  GFS ALSO SHOWS
THIS FEATURE...BUT IS MUCH SLOWER BUILDING IT SOUTH AND THUS HANGS
ON TO LIGHT PRECIP IN THE AREA INTO FRIDAY.  LEANED TOWARD TO THE
MORE AGGRESSIVE ECMWF/GEM SOLUTIONS AND WENT WITH DRY CONDITIONS
FRIDAY INTO SATURDAY.  THE HIGH WILL KEEP THE AREA IN A NORTHERLY
FLOW...WHICH WILL PROVIDE COOLER CONDITIONS WITH SLIGHTLY BELOW
SEASONAL NORMALS INTO AT LEAST THE FIRST PART OF THE HOLIDAY
WEEKEND.

&&

.AVIATION...
ISSUED AT 614 PM CDT SAT MAY 18 2013

MOS GUIDANCE IS TRYING TO BRING MVFR FOG IN BY SUNSET AT MOST
SITES. WAS NOT READY TO GO THAT FAR BUT CONSIDERING LAST NIGHTS
FOG WENT AHEAD AND INTRODUCED IT. IN CONTRAST TO NORMAL MOS
ACTUALLY BRINGS PAH EVV AND OWB DOWN EARLIER AND INTO IFR CAT
OVNGT. INTRODUCED MVFR FOG AND TEMPO SOME IFR FOG AFTER 6Z. WILL
MONITOR CLOSELY FOR FOG DEVELOPMENT TIMING AND INTENSITY. LIGHT
SOUTH WINDS OVNGT AND A BIT GUSTY AT KCGI AFTER 18Z SUNDAY.

&&

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

$$

UPDATE...KH
AVIATION...KH