Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 310235
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
935 PM CDT WED JUL 30 2014

.UPDATE...A FEW LIGHT SHOWERS MAY MAKE IT INTO THE FAR NRN CWA
FROM CENTRAL WI OVER THE NEXT FEW HOURS. OTHERWISE THE MAIN
SHORTWAVE TROUGH WILL TRACK FROM THE NRN GREAT LAKES TO THE ERN
GREAT LAKES DURING THE OVERNIGHT. FOR THU AFTERNOON AND EVENING
THE MODELS TAKE ONE SHORTWAVE TROUGH ACROSS NE WI INTO LOWER MI
WITH ANOTHER ACROSS IA. A SFC TROUGH IS PRESENT OVER NE WI WITH
THE AFOREMENTIONED SHORTWAVE TROUGH. SO OVERALL THE ORGANIZED
AREAS OF LIFT ARE TO THE NORTH AND THE SW BUT STILL WOULD EXPECT
ISOLD TO SCT SHOWER AND TSTORM DEVELOPMENT GIVEN BETTER OVERALL
CYCLONIC FLOW WHEN COMPARED TO TODAY.


&&

.AVIATION/06Z TAFS/...VFR CONDITIONS TO PREVAIL FROM EARLY THU
THROUGH THU NT. HOWEVER THERE WILL BE 30-40 PERCENT CHANCES OF
SHOWERS AND THUNDERSTORMS FOR THU AFTERNOON AND EVENING AS MORE OF
A CYCLONIC FLOW AFFECTS THE REGION.


&&

.PREV DISCUSSION... /ISSUED 357 PM CDT WED JUL 30 2014/

TONIGHT AND THURSDAY...FORECAST CONFIDENCE IS MEDIUM.

MAIN 500 MB VORTICITY MAXIMUM WITHIN NORTHWEST FLOW WILL PASS
NORTHEAST OF THE AREA THROUGH THE EVENING. THERE IS NOT MUCH ELSE
THAT WOULD HELP GENERATE UPWARD VERTICAL MOTION BESIDES MIXING WITH
CURRENT HEATING OVER THE AREA.

AREA FORECAST SOUNDINGS STILL SHOWING A COUPLE HUNDRED J/KG OF MEAN
LAYER CAPE...THOUGH MOST IS SHALLOW. WILL LOWER POPS SLIGHTLY INTO
THE EVENING...JUST IN CASE SHOWERS DEVELOP. REMOVED ISOLATED THUNDER
WORDING...AS NOT SEEING MUCH MEAN LAYER CAPE ABOVE THE 10 BELOW ZERO
CELSIUS LEVEL. SOME UNCERTAINTY HERE WITH THE POPS...AND COULD END
UP BEING A DRY PERIOD.

SKIES SHOULD BECOME MOSTLY CLEAR BY LATER THIS EVENING INTO THE
OVERNIGHT HOURS. 925 MB TEMPERATURE FIELDS SUGGEST LOWS DROPPING
INTO THE MID 50S TO AROUND 60.

NAM AND GFS SHOWING BIG DIFFERENCES WITH MEAN LAYER CAPE VALUES ON
THURSDAY AFTERNOON. NAM SHOWING 1000 TO 1200 J/KG...WITH GFS SHOWING
PERHAPS HALF THAT AT BEST. NAM CAN BE TOO AGGRESSIVE WITH THESE
VALUES...SO LEANED MORE TOWARD THE GFS VALUES. STILL...ENOUGH TO
BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON.
MAY SEE MORE AREAL COVERAGE OF STORMS GIVEN THE GFS MEAN LAYER CAPE.
HIGHS SHOULD REACH THE UPPER 70S TO LOWER 80S IN MOST AREAS. MAY SEE
LAKE BREEZE LATE IN THE DAY SOUTH OF MILWAUKEE.

SHORT TERM...THURSDAY NIGHT THROUGH SATURDAY NIGHT.

THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM

VORT MAX IN BASE OF SHORT WAVE TROUGH CROSSES SRN WI BETWEEN 00Z AND
12Z FRIDAY. DCVA-DRIVEN MID-UPPER LAYER Q-VECTOR CONVERGENCE AND
FRONTOGENETIC RESPONSE INCREASES AFTER 00Z FRIDAY...MAXING OUT AT
06Z...THEN LOWERING/MOVING SE OUT OF CWA BY 12Z FRIDAY. WILL HAVE
CHANCE/SLIGHT CHANCE POPS IN PRIOR TO 06Z...THEN SLIGHT CHANCE
FROM 06Z TO 12Z IN THE SOUTHEAST CORNER.

FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE LOW

WILL HAVE CHANCE POPS IN THE MORNING OVER THE SOUTHEAST WITH
FORCING FROM THURSDAY NIGHT VORT MAX RETURNING AS IT ROTATES IN
BASE OF DEEPENING TROUGH...AND IN THE NORTH WITH INCREASING
FORCING AHEAD OF NEXT SHORT WAVE TROUGH THAT DROPS INTO NRN WI BY
00Z SAT WITH THE TROUGH AXIS REACHING THE FAR SE CORNER OF THE
STATE BY 12Z SATURDAY. NAM SLOWER WITH SHORT WAVE TROUGH AND OMEGA
DOESN`T MAX OUT UNTIL 00Z SAT OR LATER...BUT NOT CONFIDENT IN
SLOWER SOLUTION TO LOWER LIKELY POPS FOR FRIDAY AFTERNOON.
CONSENSUS SOLUTION ONLY SUPPORTS CHANCE POPS IN THE NE OVERNIGHT
AND SLIGHT CHANCE ELSEWHERE.

SATURDAY AND SATURDAY NIGHT...FORECAST CONFIDENCE LOW

MODELS CONTINUE TO STRUGGLE WITH LOCATION OF TROUGH AND WESTWARD
EXTENT OF VORTICITY MAXIMA SPINNING IN THE BASE OF THE TROUGH.
COMPROMISE BETWEEN THE SLOWEST CANADIAN GEM AND THE GFS AND ECMWF
LIMITS CHANCE POPS DURING THE DAY SATURDAY TO THE SOUTHEAST TWO-
THIRDS OF THE CWA AND SLIGHT CHANCES ELSEWHERE...WITH SHORT WAVE
RIDGING PUSHING ALL THE PCPN OUT OF SRN WI BY 00Z SUNDAY.

LONG TERM...SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE LOW

TROUGH FINALLY MOVES FAR ENOUGH EAST TO ALLOW WEAK UPPER RIDGING
AND HIGH PRESSURE TO PUSH INTO THE WESTERN GREAT LAKES REGION.
MODEL DIFFERENCES WITH AMPLITUDE OF WESTERN RIDGE LEAD TO LOCATION
DIFFERENCES WITH UPPER JET AND TRACK OF SHORT WAVES INTO MONDAY
NIGHT...WITH NRN WI HAVING THE BETTER CHANCE OF SEEING PCPN EARLY
NEXT WEEK ALONG A FRONT/WEAK SFC TROUGH THAT SLOWLY SAGS SOUTH
WITH TIME THEN STALLS AS MODELS EVOLVE INTO A PSEUDO- ZONAL FLOW
AS RIDGE HEELS OVER AND FLATTENS. BLENDED SOLUTION BRINGS LOW
CHANCE POPS BACK INTO NRN CWA SUNDAY NIGHT WITH CHANCE POPS
MONDAY INTO TUESDAY ALONG SAGGING BOUNDARY. APPROACHING BROAD LOW
AMPLITUDE TROUGH SPREADS CHANCE POPS ACROSS ALL OF THE CWA
WEDNESDAY/WEDNESDAY NIGHT.


AVIATION/00Z TAFS/...

SCATTERED TO BROKEN CUMULUS CLOUDS WILL LINGER INTO EARLY THIS
EVENING ACROSS TAF SITES. ISOLATED TO SCATTERED SHOWERS SHOULD
DEVELOP BY LATE AFTERNOON AND LINGER UNTIL EARLY EVENING. WILL USE
VICINITY SHOWER WORDING IN TAFS FOR NOW DURING THIS TIME. LIGHT
NORTH WINDS ARE EXPECTED AT MADISON...WITH LIGHT TO MODERATE EAST
WINDS AT THE EASTERN SITES.

LIGHT WINDS AND MOSTLY CLEAR SKIES ARE EXPECTED BY LATER THIS
EVENING INTO EARLY THURSDAY MORNING. MORE SCATTERED TO BROKEN
CUMULUS WILL DEVELOP BY MIDDAY THURSDAY...LINGERING INTO EARLY
THURSDAY EVENING. SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS ARE
EXPECTED DURING THIS TIME. USED VICINITY WORDING IN TAFS FOR NOW.
LIGHT TO MODERATE WEST SOUTHWEST WINDS WILL PREVAIL THURSDAY.

&&

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

$$

UPDATE...GEHRING
TONIGHT/THURSDAY AND AVIATION/MARINE...WOOD
THURSDAY NIGHT THROUGH WEDNESDAY...REM


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