Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 291421
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
921 AM CDT SUN MAR 29 2015

.UPDATE...
ISSUED AT 921 AM CDT SUN MAR 29 2015

CLEANED UP THE HOURLY POP GRIDS AND BROUGHT TEMPERATURES UP FASTER
THROUGH 17Z THAN FORECAST. THE DIURNAL TREND HAS BEEN TOO SLOW
CAPTURING THE INCREASINGLY RAPID WARM UPS WE ARE SEEING WITH THE
INCREASED SUN ANGLE IN THE EARLY MORNING. THIS ALSO RESULTED IN
ADJUSTMENTS TO RH (LOWER) FOR THOSE WITH FIRE WEATHER INTERESTS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 200 AM CDT SUN MAR 29 2015

SURFACE HIGH PRESSURE OVER THE APPALACHIANS WILL SLIDE EAST OVER
THE ATLANTIC...AS A SHORT WAVE DRIVES A COLD FRONT INTO THE OHIO
VALLEY LATER THIS AFTERNOON. CONVERGENCE SHOWERS WILL OCCUR ALONG
AND JUST AHEAD OF THE FRONT THIS AFTERNOON...AND WORK THEIR WAY
SOUTH ACROSS THE FA THROUGH THIS EVENING. THE FRONT WILL HAVE
NEARLY COMPLETELY MADE PASSAGE BY 06Z...WITH SHOWERS EFFECTIVELY
ENDING BY/AROUND MIDNIGHT TONIGHT.

SURFACE HIGH PRESSURE BUILDS ACROSS THE MID MISSIPPI AND TENNESSEE
VALLEY IN THE WAKE OF THE FRONT`S DEPARTURE MONDAY. THIS WILL HELP
TEMPS THAT WERE IN THE 50S SUNDAY...RECOVER INTO THE 60S FOR
MONDAY. THE HIGH SHIFTS EAST TUESDAY...ALLOWING RETURN FLOW TO
NUDGE THE MERCURY UPWARDS TOWARD 70 DEGREES FOR TUESDAY HIGHS.
LOWS LIKEWISE WILL MODERATE FROM THE 30S TONIGHT TO 40S TOMORROW
NIGHT. MODELS DIFFER ON AMOUNT OF MOISTURE ADVECTION ALONG WITH
THE WARM ADVECTION...SO FOR NOW WE WILL LEAVE TUESDAY DRY IN THE
FORECAST...BUT A SMALL POP MAY EVENTUALLY BE WARRANTED.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN MAR 29 2015

A QUASI-ZONAL/LOW AMPLITUDE FLOW PATTERN WILL DOMINATE THE CONUS
DURING THE LONG TERM PERIOD. THIS IS A SHARP DEPARTURE FROM THE VERY
PERSISTENT WEST COAST RIDGE/EASTERN TROUGH PATTERN OF THE PAST
COUPLE MONTHS. THE MAIN FEATURE OF INTEREST WILL BE A LOW-AMPLITUDE
SHORTWAVE TROUGH THAT WILL MIGRATE EASTWARD FROM THE ROCKIES ACROSS
THE MID/UPPER MISSISSIPPI VALLEY THURSDAY THROUGH FRIDAY. THIS
SHORTWAVE AND ITS ASSOCIATED COLD FRONT WILL PRODUCE A ROUND OF
SHOWERS AND STORMS.

LOOKING AT THE SPECIFIC DETAILS...A LOW-AMPLITUDE 500 MB RIDGE WILL
PROGRESS EAST ACROSS THE MISSISSIPPI VALLEY WEDNESDAY. ON THE FRONT
SIDE OF THIS RIDGE...A WEAK SHORTWAVE WILL MOVE SOUTHEAST ACROSS OUR
REGION TUESDAY NIGHT. SOME SHOWERS AND ISOLATED STORMS ARE POSSIBLE
WITH THIS FEATURE TUESDAY NIGHT.

ON WEDNESDAY...THE AFOREMENTIONED 500 MB RIDGE SHOULD BRING RATHER
WARM AND DRY CONDITIONS FOR MOST OF THE REGION. HOWEVER...A WEAK
SHORTWAVE WILL UNDERCUT THE RIDGE. THIS SHORTWAVE WILL PASS EAST
ACROSS THE LOWER MISSISSIPPI VALLEY...POSSIBLY BRINGING SOME SHOWERS
AND STORMS AS FAR NORTH AS SOUTHEAST MISSOURI AND SOUTHWEST
KENTUCKY. THE MOIST AND MARGINALLY UNSTABLE SOUTHERLY LOW LEVEL FLOW
WILL BE CONDUCIVE FOR DIURNALLY DRIVEN ACTIVITY.

ON WEDNESDAY NIGHT AND THURSDAY...SHOWERS AND THUNDERSTORMS WILL
GRADUALLY INCREASE AHEAD OF A SOUTHEASTWARD MOVING COLD FRONT. A
MODERATELY STRONG SOUTHWEST FLOW WILL RAISE BOUNDARY LAYER DEW
POINTS INTO THE LOWER 60S. A LOW-AMPLITUDE SHORTWAVE WILL LAG FAR TO
OUR WEST OVER THE ROCKIES...WHICH WILL BE A LIMITING FACTOR FOR
PRECIP COVERAGE. WILL KEEP POPS MAINLY IN THE CHANCE CATEGORY.

THURSDAY NIGHT INTO FRIDAY...THE AFOREMENTIONED SHORTWAVE WILL MOVE
RAPIDLY EASTWARD ACROSS THE PLAINS. THE ASSOCIATED COLD FRONT WILL
MOVE SOUTHEAST INTO THE LOWER OHIO VALLEY BY FRIDAY MORNING. POPS
WILL BE IN THE LIKELY CATEGORY IN SOME AREAS DURING THIS TIME FRAME.
AS FAR AS SEVERE WEATHER POTENTIAL GOES...THERE IS STILL A LOT OF
MODEL VARIABILITY CONCERNING THE FRONTAL TIMING FRIDAY. IF THE FRONT
WERE TO CROSS OUR REGION FRIDAY AFTERNOON AS THE 12Z ECMWF AND ITS
ENSEMBLE MEAN INDICATED...MOST OF THE WIND AND INSTABILITY
PARAMETERS WOULD BE FAVORABLE FOR SEVERE WX. HOWEVER...THE 00Z
GUIDANCE SUITE IS FASTER WITH THE FRONTAL MOVEMENT. THE FASTER
MOVEMENT SUGGESTS THE FRONT WOULD CROSS OUR REGION DURING THE COOLER
AND MORE STABLE HOURS THURSDAY NIGHT/EARLY FRIDAY.

IN ANY CASE...FRIDAY NIGHT AND SATURDAY WILL BE COOLER AND DRIER IN
THE WAKE OF THE FRONT. GIVEN THE LOW AMPLITUDE OF THE FLOW
PATTERN...THE HIGH SHOULD BE RELATIVELY WEAK...WHICH IS IN AGREEMENT
WITH THE MODEL GUIDANCE. EVEN SO...SOME PATCHY FROST COULD NOT BE
RULED OUT FRIDAY NIGHT.

&&

.AVIATION...
ISSUED AT 200 AM CDT SUN MAR 29 2015

A COLD FRONT WILL MOVE IN FROM THE NORTH LATER TODAY...ALLOWING
CLOUDS TO INCREASE WITH MID DECK CIGS DEVELOPING BY THIS PM. THESE
CIGS MAY PRODUCE A PASSING SHOWER THIS AFTERNOON OR EVENING AS THE
FRONT MAKES ITS PASSAGE. CLOUDS SHOULD DISPERSE AGAIN AFTER
MIDNIGHT AS THE FRONT DEPARTS AND HIGH PRESSURE BUILDS IN ITS
WAKE.

&&

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

$$



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