000
FXUS63 KGRB 120437
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1037 PM CST WED DEC 11 2013

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SYNOPSIS...
ISSUED AT 307 PM CST WED DEC 11 2013

CONTINUED WELL BELOW NORMAL TEMPERATURES WITH SOME LIGHT SNOW AND
FLURRIES AT TIMES.

THE UPR PATTERN WL REMAIN DOMINATED BY OVERALL HIGH UPR HEIGHTS
FM THE ERN PAC NWWD ACRS THE BERING STRAITS AREA AND INTO NERN
ASIA. THAT WL BASICALLY BLOCK THE FLOW OF PACIFIC AIR MASSES INTO
WRN NOAM...AND ALLOWING THE GENERATION OF FRIGID AIR ACRS CANADA
TO CONT UNIMPEDED. SO ALTHOUGH THE FLOW ACRS NOAM MAY LOSE SOME
AMPLITUDE WITH TIME...IT/S GOING TO BE VERY TOUGH GET SIG WARMING.
TEMPS WL START OUT WAY BLO NORMAL AND REMAIN SO THROUGH THE
WEEKEND. THERE MAY BE SOMEWHAT OF A WARMUP /JUST BACK TO NORMAL/
DURING THE EARLY TO MIDDLE PART OF NEXT WEEK...BUT IT SEEMS LIKELY
WE/LL DROP BACK TO BLO NORMAL AGAIN AFTER THAT. THE FAST UPR FLOW
WL BRING NUMEROUS DISTURBANCES EWD IN THE STG BAROCLINIC ZONE NEAR
THE RGN. THOSE WL LIKELY GENERATE SEVERAL ROUNDS OF LGT SNOW. BUT
MOISTURE WL BE LIMITED...SO PCPN AMNTS WL PROBABLY END UP BLO
NORMAL FOR THE PERIOD.
&&

.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 307 PM CST WED DEC 11 2013

AM GOING TO SIMPLIFY THE WIND CHILL ADVISORY BY ADJUSTING THE
LAKESHORE TO START IMMEDIATELY...SO WE/LL HAVE AN ADVISORY FOR
THE WHOLE AREA UNTIL 15Z TOMORROW. CONDITIONS THERE NOT REALLY ANY
DIFFERENT THAN JUST TO THE WEST WHERE WE HAVE THE ADVISORY ONGOING.
IN ADDITION...THE NORTH MAY FLIRT WITH WARNING CRITERIA...BUT SITN
NOT CLEAR-CUT ENOUGH TO UPGRADE THEM.

THE MAIN FCST ISSUE TNGT WL BE AREA OF WK LIFT SWEEPING IN FM THE
W DUE TO ISENT UPGLIDE AND SOME DIV IN LFQ OF UPR JET SLIDING SE
FM CANADA. IT/S UNSUALLY NOT HARD FOR THESE TYPE OF SYSTEMS TO
GENERATE SNOW IN A COLD AIR MASS LIKE THE ONE WE HAVE ACRS THE
AREA. WENT WITH LIKELY POPS ACRS THE SW PART OF THE FCST AREA
AFTER MIDNIGHT. TENDENCY SHOULD BE FOR PCPN BAND TO DECR SOMEWHAT
AS IT SHIFTS E. A FEW LCNS IN CENTRAL WI COULD GET UP TO AN INCH
OF SNOW...WITH LESS EXPECTED TO THE N AND E.

ALTHOUGH TEMPS ALOFT WL WARM SOME ON THU...SUSPECT TEMPS AT THE
SFC WL BE MUCH SLOWER TO REACT. TRIMMED MAX TEMPS A BIT...TOWARD
THE COLDER END OF THE GUIDANCE.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 307 PM CST WED DEC 11 2013

NORTHWEST FLOW ALOFT WILL PREVAIL ACROSS THE WESTERN GREAT LAKES
REGION INTO EARLY NEXT WEEK...WITH A TRANSITION TO MORE ZONAL FLOW
EXPECTED AROUND THE MIDDLE OF NEXT WEEK.

A TIGHT BAROCLINIC ZONE...EXTENDING FROM BRITISH COLUMBIA TO THE
WESTERN GREAT LAKES REGION...IS EXPECTED TO REMAIN ACROSS THE AREA
THROUGH THE END OF THE WORK WEEK. THE 12Z NAM WAS SHOWING A
NORTHWEST-SOUTHEAST ORIENTED SWATH OF QPF INTO NORTHERN WISCONSIN
ON THURSDAY NIGHT. 12Z ECMWF...12Z GFS AND 12Z UKMET DID NOT HAVE
THE QPF AS FAR SOUTHEAST AS WISCONSIN...WHILE THE 12Z GEM-NH DID.
THIS APPEARED TO BE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF A
250MB JET MAX SINCE IT WAS WELL BEHIND THE SURFACE BOUNDARY AND
THERE DID NOT APPEAR TO BE MUCH MID LEVEL SHORT WAVE ENERGY. HAVE
OPTED TO GO WITH LOW END CHANCE POPS NEAR THE UPPER MICHIGAN
BORDER AND SLIGHT CHANCE A LITTLE FARTHER TO THE SOUTH.

SURFACE HIGH PRESSURE TO THE NORTH AND AN INVERTED TROUGH TO THE
SOUTH SHOULD CAUSE WINDS TO SHIFT MORE TO THE NORTHEAST FOR
FRIDAY...SO THERE WILL BE A CHANCE FOR SNOW IN THE EAST WITH
SLIGHT CHANCES FARTHER INLAND. THE INVERTED TROUGH...NORTHEAST TO
EAST SURFACE FLOW...AND MID LEVEL SHORT WAVE SHOULD BRING SNOW TO
THE SOUTHEAST PART OF THE FORECAST AREA FRIDAY NIGHT. CHANCES FOR
SNOW CONTINUE THROUGH SATURDAY NIGHT AS A MID LEVEL SHORT WAVE
AND SURFACE LOW PASS NORTH OF THE STATE.

THERE IS A CHANCE FOR SNOW IN CENTRAL AND NORTH CENTRAL WISCONSIN
ON MONDAY AND ACROSS THE ENTIRE AREA MONDAY NIGHT AS THE NEXT
UPPER SYSTEM PUSHES THROUGH THE STATE AND A SURFACE LOW PASSING
NORTH OF THE BORDER DRAGS A FRONT ACROSS THE AREA.

SNOW COVER AND NORTHWEST FLOW WILL HELP TO KEEP TEMPERATURES BELOW
NORMAL FOR THIS TIME OF YEAR...THOUGH A BIT OF A WARMING TREND IS
EXPECTED EARLY NEXT WEEK AS UPPER FLOW SHIFTS MORE TO THE WEST.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1024 PM CST WED DEC 11 2013

A WEAK SHORT WAVE WITH A COLD FRONT PASSAGE WILL SLIDE OVER THE
STATE EARLY THURSDAY MORNING. INCREASING MID LEVEL VFR CIGS CAN BE
EXPECTED TONIGHT. A BRIEF PERIOD OF LIGHT SNOW WITH THE FROPA MAY
PRODUCE SCATTERED MVFR CIGS AND VSBYS EARLY THURSDAY MORNING.
VFR CONDITIONS EXPECTED TO RETURN LATER THURSDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 9 AM CST THURSDAY FOR WIZ005-010>013-
018>022-030-031-035>040-045-048>050-073-074.
&&

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......MG
AVIATION.......TDH