Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 040453
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1253 AM EDT TUE AUG 4 2015

...UPDATED AVIATION DISCUSSION...

...FORECAST UPDATE...
ISSUED AT 938 PM EDT MON AUG 3 2015

CONVECTION ALONG THE COLD FRONT NEVER REALLY GOT GOING OVER
INDIANA...BUT STORMS OVER NORTHERN KENTUCKY AND SW OHIO DID PRODUCE
OUTFLOW. THIS SPARKED CONVECTION THAT CONTINUES TO BACKBUILD OVER
THE NORTHERN BLUEGRASS. THREAT FOR STRONG/SEVERE STORMS SEEMS TO BE
DIMINISHING...BUT THERE COULD BE FLASH FLOODING ISSUES WHERE STORMS
CONTINUE TO TRAIN FOR THE NEXT HR OR TWO.

SOUTHERN INDIANA AND THE REMAINDER OF CENTRAL KENTUCKY APPEAR TO BE
ON TRACK FOR A DRY NIGHT...AS FOCUS FOR CONVECTION IS PRETTY WELL
GONE WITH THE LOSS OF HEATING. GRIDS HAVE BEEN TWEAKED ACCORDINGLY
AND UPDATED TEXT PRODUCTS ON THE WAY SHORTLY.

.SHORT TERM (NOW THROUGH TUESDAY NIGHT)...
ISSUED AT 823 PM EDT MON AUG 3 2015

IN THE NEAR TERM, SKIES WERE SUNNY ACROSS THE REGION WITH
TEMPERATURES RANGING FROM THE MID-UPPER 80S IN THE NORTH TO THE
LOWER 90S IN THE SOUTH.  REGIONAL SATELLITE AND RADAR IMAGERY SHOWS
CONVECTION DEVELOPING ALONG A BOUNDARY UP INTERSTATE 70 IN CENTRAL
INDIANA. AMDAR SOUNDINGS OUT OF COVINGTON AND LOUISVILLE STILL SHOW
A BIT OF CAPPING WHICH SHOULD KEEP CONVECTION MINIMIZED FOR THE NEXT
SEVERAL HOURS.  HOWEVER, COMBINATION OF COLD FRONT SINKING SOUTHWARD
ALONG WITH SOME MODIFICATION IN THE CAP LATER THIS AFTERNOON/EVENING
SHOULD ALLOW SCATTERED SHOWERS AND STORMS TO DEVELOP.  CURRENT
THINKING IS THAT BEST COVERAGE WILL BE ACROSS OUR NORTHEASTERN
SECTIONS, MAINLY EAST OF INTERSTATE 65.  THEREFORE, WILL CONTINUE
CHANCE POPS FOR THIS EVENING WITH THE EXPECTATION THAT CONVECTION
WILL DIMINISH TOWARD MIDNIGHT.  SOME STRONG/SEVERE CONVECTION WILL
BE POSSIBLE WITH DAMAGING WINDS AND LARGE HAIL BEING THE MAIN
THREATS.

FOR THE OVERNIGHT PERIOD, THE COLD FRONT WILL CONTINUE TO SINK
SOUTHWARD AND ASSOCIATED EVENING CONVECTION WILL DIMINISH AND FADE
AWAY.  CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED OVERNIGHT WITH
TEMPERATURES DROPPING INTO THE MID-UPPER 60S IN THE NORTH WITH UPPER
60S TO AROUND 70 IN THE SOUTH.  OVERNIGHT LOWS TUESDAY NIGHT WILL
RANGE FROM THE MID-UPPER 60S IN THE NORTH TO THE UPPER 60S TO LOWER
70S IN THE SOUTH.

FOR TUESDAY, AFOREMENTIONED FRONTAL BOUNDARY WILL BE DRAPED ACROSS
THE FORECAST AREA.  CONVECTION WILL LIKELY REDEVELOP DURING THE
AFTERNOON.  HOWEVER, COVERAGE LOOKS TO BE RATHER ISOLATED/SCATTERED
IN NATURE DUE TO A LACK OF FOCUSED FORCING.  THEREFORE, PLAN ON
LEAVING IN THE ISOLATED STORM CHANCE WITH THIS UPDATE.  STUCK CLOSER
TO THE WEIGHTED MODEL GUIDANCE FOR TEMPERATURES.  THIS WOULD SUGGEST
HIGHS IN THE MID-UPPER 80S IN THE NORTH WITH UPPER 80S TO AROUND 90
IN THE SOUTH.
!--NOT SENT--!

.LONG TERM (WEDNESDAY THROUGH MONDAY)...
ISSUED AT 320 PM EDT MON AUG 3 2015

WESTERN CONUS RIDGING WILL BE IN PLACE THROUGH THE LONG TERM.
MEANWHILE, TROUGHING WILL BE ESTABLISHED THROUGHOUT THE NORTHEAST
CONUS. THE OHIO RIVER VALLEY WILL BE SITUATED IN NORTHWEST FLOW
ALOFT BETWEEN THESE TWO FEATURES. INDIVIDUAL DISTURBANCES WILL MOVE
ACROSS THE AREA, THE STRONGEST OF WHICH WILL OCCUR WEDNESDAY-
THURSDAY. A DRIER PATTERN WILL TAKE OVER FOR THE WEEKEND, BEFORE
ANOTHER DISTURBANCE LOOKS TO ARRIVE ON MONDAY.

WEDNESDAY - THURSDAY...

MODELS CONTINUE TO AGREE ON A SHORTWAVE MOVING FROM THE EASTERN
PLAINS WEDNESDAY MORNING, THROUGH OUR AREA BY THURSDAY EVENING.
HOWEVER, MODELS SLIGHTLY DISAGREE ON THE EXACT TIMING AND PLACEMENT.
AT THE SURFACE, A FRONTAL BOUNDARY WILL BE NEAR OUR WESTERN CWA ON
WEDNESDAY MORNING, SLOWLY LIFTING NORTHEAST AS A WARM FRONT THROUGH
THURSDAY. THIS WILL OCCUR AS A SURFACE LOW DEVELOPS AHEAD OF THE
SHORTWAVE AND TRACKS ACROSS THE CWA THROUGH THURSDAY. AMPLE DEEP
MOISTURE WILL POOL AHEAD OF THE SYSTEM AND COMBINE WITH INSTABILITY
TO CREATE NUMEROUS THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY.
NOTICED A SLIGHTLY SLOWER TREND ON WEDNESDAY AFTERNOON SO WILL KEEP
HIGHEST COVERAGE WEST OF I-65 NEAR THE WARM FRONTAL BOUNDARY.

CAN`T RULE OUT A FEW STRONGER STORMS DURING THIS TIME FRAME AS
PLENTY OF INSTABILITY WILL BE PRESENT ALONG AND SOUTHWEST OF THE
RETREATING WARM FRONT. HOWEVER, DEEP LAYER SHEAR VALUES CONTINUE TO
LOOK MARGINAL (20-30 KNOTS) FOR ORGANIZATION. MORE CONCERNED WITH
THE POTENTIAL FOR HEAVY RAINFALL AS HIGHER PRECIPITABLE WATER VALUES
WILL COUPLE WITH A SLOW MOVING FRONT AND OVERALL SYSTEM. IN FACT,
WPC HAS PLACED MUCH OF KENTUCKY IN A SLIGT RISK FOR EXCESSIVE
RAINFALL.

THURSDAY NIGHT - FRIDAY NIGHT...

THE SYSTEM WILL MOVE OFF TO THE EAST BY THURSDAY NIGHT, WITH DRIER
NORTHWEST FLOW TAKING OVER. WILL LEAVE LINGERING CHANCES IN THE
EAST. SOME DATA STILL SUGGESTS THAT A SECONDARY DISTURBANCE WILL
CROSS THE NORTHWEST FLOW ALOFT THROUGH FRIDAY EVENING, WILL HAVE
SMALL CHANCES TO ACCOUNT FOR THIS. PREFER TO LEAN TOWARD THE DRIER
SOLUTION SUGGESTED BY THE NAM/ECMWF AS WE WILL BE IN THE SUBSIDENT
WAKE OF THE FIRST UPPER SYSTEM AND DEEPER MOISTURE WILL BE HARD TO
COME BY. THIS PERIOD WILL BE MARKED BY COOLER TEMPERATURES, WITH
HIGHS IN THE LOW-MID 80`S AND LOWS IN THE 60`S.

SATURDAY - SUNDAY NIGHT...

DATA CONTINUES TO INDICATE DRY NORTHWEST FLOW ALOFT THROUGH THE
WEEKEND SO WILL KEEP THINGS DRY WITH TEMPERATURES MORE SOLIDLY IN
THE 80`S. LOWS WILL BE SLIGHTLY MILDER IN THE MID TO UPPER 60`S.

MONDAY...

LOW CONFIDENCE TO START THE NEW WORK WEEK. HOWEVER, THERE IS GENERAL
AGREEMENT IN ANOTHER DISTURBANCE APPROACHING IN THE NORTHWEST FLOW
ALOFT. WILL LEAVE SMALL CHANCES IN THE FORECAST WITH TEMPERATURES IN
THE HIGH 80`S TO AROUND 90.

&&

.AVIATION (06Z TAF UPDATE)...
ISSUED AT 1250 AM EDT TUE AUG 4 2015

LIGHT/VARIABLE WINDS AND MOISTURE POOL ALONG STALLING SURFACE FRONT
AND CONVECTIVE OUTFLOW BOUNDARIES MAY ALLOW LIGHT FOG TO DEVELOP AT
BWG AND LEX DURING THE PRE-DAWN HOURS. FOR THE REMAINDER OF
TODAY...VFR CONDITIONS EXPECTED AT ALL SITES WITH WINDS AT OR BELOW
10 KTS. DURING PEAK HEATING THIS AFTERNOON...AN APPROACHING WEATHER
SYSTEM AND INTERACTION WITH THE AFOREMENTIONED SURFACE BOUNDARIES
MAY RESULT IN ISOLATED TO WIDELY SCATTERED SHOWERS/STORMS.
HOWEVER...ENVIRONMENT IS NOT SUPPORTIVE OF HIGH COVERAGE SO WILL
LEAVE OUT OF TAF AT THIS POINT. PLAN ON LIGHT/VARIABLE WINDS AGAIN
TONIGHT...WITH INCREASING HIGH CLOUDS FROM THE WEST BY THE END OF
THE PERIOD.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&

$$

UPDATE.........RAS
SHORT TERM.....MJ
LONG TERM......BJS/CEA
AVIATION.......ZBT



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