Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 150820
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
320 AM CDT WED APR 15 2015

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 320 AM CDT WED APR 15 2015

THE DRIER SOLUTION FOR TUESDAY, ADVERTISED 4 TO 5 DAYS AGO, APPEARS
TO HAVE BEEN ON TRACK, AS RIDGING DEVELOPED ALOFT AHEAD OF THE
ROCKIES LOW/TROUGH AND THE STALLED OUT SURFACE FRONT TO THE
SOUTHEAST OF THE WFO PAH FORECAST AREA BECAME MORE OF AN INVERTED
TROUGH WITH TIME.

STARTING TODAY (WEDNESDAY), THE DRIER EASTERLY FLOW AT LOW LEVELS
WILL INHIBIT THE TRANSLATION OF PRECIPITATION FROM SOUTHWEST TO
NORTHEAST INTO LATE THIS AFTERNOON, WHEN SURFACE FLOW BECOMES MORE
SOUTHEASTERLY, THEN SOUTH IN AGEOSTROPHIC RESPONSE TO A SHARP, NORTH
TO SOUTH ORIENTED SHORTWAVE, EJECTED EAST FROM THE ROCKIES LOW,
MOVES THROUGH THE QUAD STATE REGION.

THE MOST DYNAMIC LIFT WOULD BE EXPECTED THIS EVENING, SO KEPT THE
HIGHEST POPS OVER THE EASTERN 1/2 OF THE WFO PAH FORECAST AREA,
FOCUSED ON THE PENNYRILE REGION OF WEST KENTUCKY.

DECENT RIDGING ALOFT DEVELOPS AGAIN AHEAD OF THE CLOSED LOW IN THE
ROCKIES, LIMITING CONVECTIVE ACTIVITY FROM WEST TO EAST THURSDAY
INTO THURSDAY NIGHT. FOR COLLABORATIVE PURPOSES, A SMALL MENTION OF
POPS WAS KEPT IN THE EASTERN SECTIONS OF SOUTHWEST INDIANA AND THE
PENNYRILE REGION OF WEST KENTUCKY. AT THIS POINT, HAVE VERY LOW
CONFIDENCE THAT ANY MEASURABLE PRECIPITATION WILL OCCUR IN THE
AFOREMENTIONED AREAS THURSDAY NIGHT.

FOR FRIDAY, BELIEVE THAT THE LOW CHANCE POPS/WEATHER MAY BE
OVERDONE, EVEN THOUGH THE CLOSED LOW OVER THE ROCKIES BEGINS TO
SLOWLY TRANSLATE EAST-SOUTHEAST INTO THE FRONT RANGE. AGAIN, FOR
COLLABORATIVE PURPOSES, ATTEMPTED TO BLEND HIGHER POP FORECASTS FROM
SURROUNDING OFFICES, WHILE TRYING TO MAIN INTERNAL INTEGRITY OF
LITTLE OR NO POPS TO THE NORTH PART OF THE WFO PAH FORECAST AREA.

UNTIL THAT UPPER LOW EJECTS OUT TOWARD THE MISSISSIPPI VALLEY, RAIN
CHANCES SHOULD REMAIN MINIMAL.  THIS IS A FAR CRY FROM THE VERY
DYNAMIC AND VOLATILE TRANSLATION AND MOVEMENT OF THE LOW OVER THE
WFO PAH FORECAST AREA EARLY THIS WEEK, BASED ON A SET OF VERY
AGGRESSIVE MODEL RUNS OF THE GFS.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 AM CDT WED APR 15 2015

THE 00Z OPERATIONAL RUNS OF THE GFS AND ECMWF ARE ACTUALLY IN VERY
GOOD AGREEMENT IN TIMING PRECIPITATION THROUGH THE AREA THROUGH
THE WEEKEND...SO TRIED TO PUSH THE FORECAST AS MUCH AS POSSIBLE
TOWARD THEIR SOLUTION.

THE PRIMARY WEATHER-MAKER FOR OUR REGION WILL BE A CLOSED UPPER-
LEVEL LOW CENTER THAT BEGINS OVER THE SOUTHERN ROCKIES FRIDAY
EVENING. A WEAKER UPPER-LEVEL DISTURBANCE IN THE WEAK SOUTHWEST
FLOW TO ITS EAST WILL STREAM OVER OUR REGION LATE SATURDAY INTO
SUNDAY MORNING. THEN THE ROCKIES LOW WILL BE DRAWN INTO A HEALTHY
UPPER SYSTEM DIGGING ITS WAY INTO THE NORTHERN ROCKIES BY 12Z
SUNDAY. THESE 2 SYSTEMS WILL COMBINE TO CREATE A FAIRLY HIGH
AMPLITUDE TROUGH LOCATED RIGHT ALONG THE MISSISSIPPI RIVER BY 12Z
MONDAY.

LOOK FOR GOOD CHANCES OF SHOWERS AND THUNDERSTORMS WITH THE
DISTURBANCE SATURDAY NIGHT...AND AGAIN WITH THE MAIN TROUGH LATE
SUNDAY AND SUNDAY NIGHT. WIND FIELDS WILL BE RATHER
WEAK...ESPECIALLY WITH THE LEAD DISTURBANCE....SO THE ORGANIZED
SEVERE WEATHER THREAT APPEARS TO BE MINIMAL AT THIS TIME. LOCALLY
HEAVY RAINFALL AND FREQUENT LIGHTNING WOULD BE THE PRIMARY
CONCERNS. CANNOT RULE OUT SOME SHOWERS LINGERING INTO MONDAY AHEAD
OF THE LARGER-SCALE TROUGH...BUT THINK FORECAST POPS ARE A BIT
TOO HIGH FOR MONDAY.

BEYOND MONDAY...THE ECMWF IS A BIT MORE AMPLIFIED WITH THE LARGE
CYCLONE CENTERED OVER ONTARIO...AND KEEPS THE AREA DRY THROUGH AT
LEAST TUESDAY NIGHT. IT THEN HAS A HARD TIME PUSHING PRECIPITATION
INTO OUR REGION AS A WEAK SURFACE BOUNDARY APPROACHES WEDNESDAY.
THE GFS HAS MORE OF A ZONAL FLOW AND BRINGS A SHARPER...BUT STILL
WEAK...COLD FRONT INTO THE REGION TUESDAY NIGHT ALONG WITH SOME
SHOWERS. WILL INSERT SOME SLIGHT CHANCES OF SHOWERS TUESDAY NIGHT
INTO WEDNESDAY...BUT REALLY WOULD PREFER TO KEEP THE FORECAST
DRY...RATHER THAN TRY TO TIME SUCH PUNY FEATURES IN WHAT LOOKS
LIKE A DRY PATTERN.

AS FOR TEMPERATURES...WE WILL BE ABOVE NORMAL FOR HIGHS OVER THE
WEEKEND...AND THEN COOL DOWN TO JUST BELOW NORMAL NEXT WEEK. LOWS
WILL BE QUITE MILD OVER THE WEEKEND AND THEN TREND COOLER TOWARD
NORMAL LEVELS EARLY NEXT WEEK.

&&

.AVIATION...
ISSUED AT 1156 PM CDT TUE APR 14 2015

VFR CIGS WILL DROP TO MVFR AS SCATTERED SHOWERS MOVE NORTH TO
KCGI AND KPAH AROUND 11Z, AND KOWB AND KEVV AROUND 14Z. CIGS WILL
IMPROVE TO LOW VFR AS SHOWERS TAPER OFF BY EARLY AFTERNOON. SHOWER
CHANCES WILL INCREASE AFTER 20Z AS CIGS/VSBYS GRADUALLY DROP TO
MVFR. WINDS WILL BE OUT OF THE NORTHEAST TO EAST AT 5 TO 12 KTS
THROUGH THE TAF PERIOD.

&&

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

$$

SHORT TERM...SMITH
LONG TERM...DRS
AVIATION...RST



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