Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 270830
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
330 AM CDT WED AUG 27 2014

.TODAY AND TONIGHT...FORECAST CONFIDENCE

AREA OF SHOWERS ACROSS NRN WI MOVING AHEAD OF SHORT WAVE TROUGH AND
UPPER DIVERGENCE WITHIN RIGHT ENTRANCE REGION OF UPPER JET...WHICH
PUSH EAST OVER NRN LAKE MICHIGAN/NRN LOWER MICHIGAN LATER THIS
MORNING. LIGHT ACCAS SHOWERS/SPRINKLES OVER FORECAST AREA TIED TO
SECOND WEAKER VORT MAX AND...PER MID-UPPER LEVEL Q-VECTOR
CONVERGENCE FORECASTS...SHOULD BE EAST OF FORECAST AREA BY 12Z WITH
RAIN TOTALING ONLY TRACE AMOUNTS.

REST OF THE DAY AND INTO THE EVENING WILL BE DRY WITH SUBSIDENCE AND
WEAK COLD AIR ADVECTION BEHIND WAVE AS SURFACE HIGH PRESSURE SETTLES
OVER WISCONSIN. 925 MB TEMPS COOL TO 16C BY 18Z THEN MODIFY UPWARD
IN THE WEST TO AROUND 18C. LOWER 925MB TEMPS AND COOL NORTHEAST TO
EAST WINDS WILL HOLD HIGHS IN THE LOW 70S FROM THE KETTLE MORAINE
AND EAST...WITH MID TO UPPER 70S TO THE WEST THOUGH TEMPS THERE
COULD BE A BIT LOWER IF AFTERNOON CLOUD COVER DOES NOT THIN AS
EXPECTED

HAVE FOLLOWED OVERALL TREND OF 00Z MODELS AND SLOWED PRECIPITATION
INTO THE CWA TONIGHT. 700 MB OMEGA AND LAYER Q-VECTOR CONVERGENCE
FORECASTS SUPPORT FORCING WITH FOCUSED WARM AIR ADVECTION ON NOSE OF
LOW-LEVEL JET...AHEAD OF POSITIVELY-TILTED 500 MB TROUGH MOVING INTO
THE CENTRAL PLAINS...STAYING WEST THROUGH 12Z THURSDAY. FOLLOWED A
BLEND FOR LOW TEMPS TONIGHT WITH TEMPS COOLING INTO THE MID 50S AWAY
FROM THE LAKE IN THE EAST TO AROUND 60 WEST.

.THURSDAY THROUGH SATURDAY - CONFIDENCE...MEDIUM
ACTIVE PATTERN SETTING UP THIS PERIOD WITH CONCERN FOR FLOODING
WITH LIMITED SEVERE POTENTIAL. 850 WARM AND MOIST ADVECTION RAMPS
UP LATER THURSDAY INTO THURSDAY NIGHT WITH A STRONG ADVECTION
SIGNAL NOTED. THE NAM IS FURTHEST NORTH ON QPF BULLSEYE WITH THE
ECMWF AND GFS FURTHER SOUTH MORE INTO THE CWA...BUT THINGS ARE
SLOWING UP WITH THE GREATEST CONFIDENCE IN HIGHER POPS FOR
THURSDAY IN THE WESTERN AND NORTHERN CWA. 00Z ECMWF KEEPS FAR SE
WI DRY UNTIL AFTER 6Z THURSDAY NIGHT...SO HAVE TRIMMED POPS BACK
TO SLOW THINGS. MOISTURE SURGE EXPANDS ACROSS THE AREA IN EARNEST
ON THURSDAY NIGHT. TALL SKINNY CAPE VALUES...HIGH PRECIPITABLE
WATER VALUES...AOB 10 KNOTS AT TIMES...AND SHORTER LOW MBE/CORFIDI
VECTORS SUGGEST MAIN CONCERN WILL BE HEAVY RAINS. SO AFTER THE
MAIN WAA/MOIST ADVECTION SURGE THU/THU NGT...EXPECT MORE ROUNDS
FRIDAY/FRIDAY NIGHT WITH MAIN MID LEVEL SHORTWAVE APPROACHING FROM
THE PLAINS. CIPS ANALOGS FOR 00Z SATURDAY SHOW IMPRESSIVE SVR
POTENTIAL HOWEVER THE MID LEVEL LAPSE RATES AND 0-6KM SHEAR ARE
NEITHER SUPPORTIVE OF SVR. THE 12Z ECMWF HAS BECOME MORE IN LINE
WITH THE SLOWER GFS SOLUTION IN KEEPING THE THREAT OF RAIN/STORMS
INTO SATURDAY...SUGGESTING A MUCH LESS PROGRESSIVE LOOK. THIS WILL
BE AT A TIME WHEN THE PRIMARY MID LEVEL TROUGH MOVES THROUGH WITH
ANY WEAK LOW PRESSURE AND SURFACE BOUNDARY HAVING THE GREATEST
IMPACT. THE 00Z NAM HAS MAINTAINED THE QUICKER MOVEMENT BUT LESS
TRUSTED AT THAT RANGE.

PROXIMITY OF INITIAL WAA/MOIST ADVECTION HEAVIER PRECIP AXIS...
PERHAPS FAVORING THE NORTHERN CWA...AND WITH SUBSEQUENT EVENTS
INTO SATURDAY WITHIN AN AIRMASS CONDUCIVE TO HEAVY RAIN TOTALS
WILL ISSUE AN ESF TO HIGHLIGHT THIS ACTIVE PERIOD.

.SUNDAY - CONFIDENCE...MEDIUM
MID LEVEL RIDGING GRADUALLY WORKS IN. THE GEM AND ECMWF ARE ON
BOARD WITH A DRY SCENARIO THOUGH THE GFS IS QUICK TO RETURN TO
THE SOUTHWEST UPPER FLOW AND BRINGS PRECIP ACROSS. LEAVING THE
SMALLISH ALLBLEND POPS IN PLACE THOUGH IF THE TRENDS IN THE
GEM/ECMWF HOLD THEN FURTHER POP REDUCTION WILL BE NECESSARY.

.MONDAY AND TUESDAY - CONFIDENCE...LOW
RIGHT BACK TO AN ACTIVE SOUTHWEST UPPER FLOW WITH POTENTIAL FOR
ANOTHER ROUND OR TWO OF TSRA. THE ECMWF SWEEPS THE SYSTEM THROUGH
MONDAY WHILE THE GFS SHOWS A TWO PRONGED EVENT SPANNING BOTH DAYS
WITH A COUPLE OF DIFFERENT LOWS...ONE TO THE NORTH AND THEN
ANOTHER RIDING NORTHEAST ALONG THE FRONTAL BOUNDARY TUESDAY. THE
GEM IS SUGGESTING A BLEND OF THE TWO. WILL NOT DEVIATE FROM THE
ALLBLEND POPS AT THIS POINT.

&&

.AVIATION/12Z TAFS/...NO VSBY RESTRICTIONS OR ACCUMULATIONS WITH
LIGHT ACCAS SHOWERS/SPRINKLES FALLING FROM 7K TO 10K FT CLOUD
DECK. EXPECT THE LIGHT PCPN TO EXIT EASTERN TAF SITES BETWEEN 12Z
AND 14Z. VFR CONDITIONS THROUGH THE REMAINDER OF THE FORECAST.
LATEST MODEL TREND IS TO SLOW WARM AIR ADVECTION SHOWERS AND STORMS
INTO SRN WI UNTIL 12Z AND AFTER THURSDAY. WILL LEAVE PCPN OUT OF
TAFS...WITH ONLY VCNTY THUNDER AT MKE AFTER 15Z THURSDAY.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...COLLAR



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