000
FXUS63 KGRB 271709
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1209 PM CDT SUN JUL 27 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 348 AM CDT SUN JUL 27 2014

ISOLATED SEVERE STORMS WHICH PRODUCED LARGE HAIL OVERNIGHT...HAVE
DIMINISHED OR MOVED NORTHEAST INTO UPPER MICHIGAN EARLY THIS
MORNING. STORMS WERE IN THE UPPER DIFFLUENT REGION AHEAD OF THE
UPPER LOW APPROACHING FROM THE NORTHERN PLAINS ALONG WITH A PLUME
OF MU CAPES NEAR 2000 J/KG OVER CENTRAL WISCONSIN INTO NORTH
CENTRAL WISCONSIN. WBZ NUMBERS WERE AROUND 9000 FEET.

SATELLITE AND AREA RADARS SHOW INCREASING MID LEVEL CLOUDS WITH
ISOLATED SHOWERS OVER NORTHWEST WISCONSIN. AFTER A MORNING
LULL...WILL QUICKLY INCREASE PCPN TRENDS THIS MORNING AS THE
UPPER LOW DROPS INTO THE WESTERN GREAT LAKES REGION. ISOLATED
STORMS WERE ALREADY EMBEDDED IN THE SHOWERS WRAPPING AROUND THIS
LOW OVER NORTHERN MINNESOTA AND HEADING TOWARD THE FORECAST AREA.
WITH THE WBZ FALLING TO NEAR 8000 FEET MID DAY OR EARLY AFTERNOON
AS THE UPPER LOW OR DEEP TROUGH AXIS PASSES...THE POTENTIAL FOR HAIL
EXITS. SOME OF THE STRONGER STORMS MAY PRODUCE HAIL APPROACHING
SEVERE LEVEL CRITERIA HAIL AND WILL CONTINUE TO NOTE IN THE HWO.
FORECAST SOUNDINGS INDICATE THE STEEPEST LOW LEVEL LAPSE RATES AND
TOTAL TOTAL NUMBERS NEAR 50 WILL BE THIS MORNING INTO EARLY
AFTERNOON. MOISTURE MAY BE ABLE TO POOL ALONG THE COLD FRONT FIRST
TODAY FOLLOWED BY A TRAILING SURFACE TROUGH IN THE AFTERNOON WHERE
WINDS THEN TURN NORTH.

ISSUE FOR THIS EVENING IS HOW FAST THIS UPPER LOW OR MORE THAN
LIKELY AN OPEN DEEP TROUGH BY THEN DEPARTS TO THE EAST. MODELS
ARE IN AGREEMENT WITH QUICKLY MOVING THE PCPN TO THE EAST BY LATE
AFTERNOON OR EARLY EVENING. WILL CONTINUE TO HANG ONTO LOW END POPS
OVER EAST CENTRAL WISCONSIN EARLY THIS EVENING...BUT WILL REMOVE ANY
THUNDER MENTION DUE TO DIMINISHED INSTABILITY AND MODELS ALSO IN
GOOD AGREEMENT WITH A DRY REGION OF AIR IN THE WAKE OF THE DEEP
TROUGH TO POUR OVER THE AREA TONIGHT INTO MONDAY FOR CLEAR OR
CLEARING TREND.

COOLEST H5 AIR DOES NOT REALLY ARRIVE UNTIL MONDAY AFTERNOON OVER
NORTHEAST AND NORTH CENTRAL WISCONSIN. DID NOTE A TREND OF
INCREASING RH FROM THE NORTH FOR MONDAY AFTERNOON...WHILE A
CONSENSUS OF MODEL CU RULE DATA INDICATE SCT-BKN.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 348 AM CDT SUN JUL 27 2014

TRUNCATED DISCUSSION DUE TO STRONG STORMS.

LARGE UPPER LOW OVER HUDSON BAY FOR MUCH OF THIS PERIOD. SEVERAL
WEAK DISTURBANCES ROTATING AROUND THE LOW WILL BRING AT LEAST
SMALL CHANCE FOR SHOWERS OR TSTORMS ESPECIALLY DURING AFTERNOONS.

SIG MOISTURE WILL REMAIN WELL SOUTH OF THE AREA FOR MUCH OF THIS
FORECAST PERIOD...SO THE PROSPECT FOR WIDESPREAD RAIN DOES NOT LOOK
GOOD. BUT THERE WILL BE SEVERAL OPPORTUNITIES FOR SCATTERED LIGHT RAIN
AS SMALL-SCALE VORT MAXES DROP SOUTHEAST ACROSS THE AREA. OVERALL...ONLY
SMALL CHANGES MADE TO PREVIOUS FORECAST.

TEMPS NEAR OR A COUPLE DEGREES BELOW NORMAL MUCH OF THIS PERIOD UNDER
THE INFLUENCE OF THE LARGE UPPER LOW AND NW FLOW ALOFT.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1209 PM CDT SUN JUL 27 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE MOVING
SOUTHEAST ACROSS NORTH-CENTRAL AND NORTHEAST WISCONSIN THIS
AFTERNOON.  SMALL HAIL AND BRIEF REDUCTION OF CIGS/VSBYS TO IFR OR
MVFR LEVELS IS POSSIBLE WITHIN ANY THUNDERSTORMS.  SHOWERS AND
STORMS WILL BE EXITING THE AREA FROM NORTHWEST TO SOUTHEAST STARTING
AROUND MID TO LATE AFTERNOON.  ALONG A COLD FRONT DROPPING SOUTH...A
FEW HOUR PERIOD OF MVFR CIGS IS LIKELY TO OCCUR LATER THIS AFTERNOON
INTO EARLY THIS EVENING.  THEN ONCE THE FRONT PASSES...SKIES WILL
BECOME CLEAR THOUGH NORTH WINDS WILL REMAIN BREEZY.  SHOULD SEE GOOD
FLYING WEATHER TOMORROW WITH VFR DIURNAL CU BUILDING BY LATE
MORNING.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....TDH
LONG TERM......JKL
AVIATION.......MPC