Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KGRB 222334
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
634 PM CDT FRI AUG 22 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 215 PM CDT FRI AUG 22 2014

THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK
AREA OF LOW PRESSURE SPINNING OVER WESTERN WISCONSIN EARLY THIS
AFTERNOON. ALTHOUGH UPPER DIVERGENCE IN THE RIGHT REAR QUAD OF A
JET STREAK HAS SHIFTED OFF TO THE EAST...CONVERGENCE NORTH OF A
SURFACE WARM FRONT HAS GENERATED SCATTERED SHOWERS AND AN ISOLATED
THUNDERSTORM OVER NORTH-CENTRAL WISCONSIN. ALSO OBSERVING RATHER
BUBBLY LOOKING CU ALONG A COLD FRONTAL TYPE FEATURE MOVING INTO
CENTRAL WISCONSIN THOUGH CONVERGENCE LOOKS QUITE WEAK...AND THE
ONLY RETURNS ARE LOCATED OVER NORTHEAST IOWA. THE ATMOSPHERE IS
GROWING UNSTABLE AHEAD OF THIS TROUGH/COOL FRONT WITH ML CAPES
GROWING TO GREATER THAN 1000 J/KG...AND CIN FALLING RAPIDLY. THE
NAM CREATES CONVECTION OVER CENTRAL WISCONSIN LATER THIS
AFTERNOON...SO THIS IS SOMETHING TO KEEP AN EYE ON. INCLUDED A
ISOLATED THUNDERSTORM MENTION FOR THE REST OF THE AFTERNOON OVER
CENTRAL WISCONSIN. MEANWHILE...A LARGE UPPER TROUGH OVER THE PAC
NW WILL SHIFT EAST CAUSING A WARM FRONT TO RE-ORGANIZE OVER THE
PLAINS ON SATURDAY. PRECIP CHANCES AND FOG POTENTIAL REMAIN THE
MAIN FORECAST CONCERNS.

TONIGHT...MODELS ARE HAVING A TOUGH TIME LATCHING ON TO THAT LOW
LEVEL CIRCULATION OVER WESTERN WISCONSIN.  THE NAM AND TO A LESSER
EXTEND THE GEM APPEAR TO HAVE A BETTER HANDLE ON THIS FEATURE THAN
OTHER GUIDANCE.  BUT CONFIDENCE WILL REMAIN LOW IN ANY CASE.  BOTH
THE NAM AND GEM SHOW THIS SURFACE LOW WEAKENING LATER THIS AFTERNOON
OR THIS EVENING AND MORPHING INTO A SURFACE TROUGH OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN.  THIS WILL KEEP AN ISOLATED TO SCATTERED
THREAT OF SHOWERS AND STORMS INTO THE EVENING...AND POSSIBLY INTO
THE OVERNIGHT HOURS TOO.  THIS TROUGH WILL ALSO PROMOTE FOG DEVELOPMENT
IN THESE AREAS TONIGHT AND THINK ANOTHER DENSE FOG ADVISORY WILL BE
POSSIBLE FOR THE EARLY MORNING COMMUTE TOMORROW.  LIGHT EASTERLY
WINDS MAY ALSO ADVECT AREAS OF MARINE FOG INLAND INTO THE LAKESHORE
COUNTIES TONIGHT.  WARM AND MUGGY WITH LOWS IN THE 60S.

SATURDAY...LOW PRESSURE WILL EMERGE INTO THE CENTRAL PLAINS AHEAD OF
A DEEP PAC NW TROUGH.  THE LOW LEVEL FLOW WILL REORGANIZE AND A WARM
FRONT WILL LIFT INTO SOUTHWEST WISCONSIN IN THE AFTERNOON.  THIS
LOOKS TO BE A LITTLE SLOWER THAN YESTERDAYS RUNS AND WILL BACK OFF
PRECIP CHANCES DURING THE MORNING.  CHANCES IMPROVE DURING THE
AFTERNOON OVER CENTRAL AND NORTH-CENTRAL WISCONSIN BUT AM SKEPTICAL
SINCE THE FRONT WILL STILL BE WELL SOUTHWEST OF THE REGION AND
MID-LEVEL RIDGING SHARPENS ALOFT.  SO WILL MATCH WITH OTHER OFFICES BUT
BRING UP CONCERN TO THE NEXT SHIFT.  ONCE THE MORNING FOG AND LOW
CLOUDS BURN OFF...CONTINUED WARM AND HUMID WITH HIGHS IN THE UPPER
70S TO LOWER 80S.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 215 PM CDT FRI AUG 22 2014

SATURDAY NIGHT INTO SUNDAY...THE UPPER RIDGE GETS NUDGED TO THE
EAST A TAD WHILE A BROAD UPPER TROUGH APPROACHES FROM THE
NORTHERN AND CENTRAL PLAINS. A DEEPENING LOW PRESSURE SYSTEM WILL
LIFT NORTHWARD OVER THE NORTHERN PLAINS...AND LIFT A WARM FRONT
NORTH OVER THE AREA. SOME PROGS GENERATE SOME CONVECTION WITH THIS
FRONT SAT NIGHT INTO SUNDAY MORNING. CONVECTION MAY STRUGGLE TO
DEVELOP DUE TO PROXIMITY TO THE UPPER RIDGE SO KEPT POPS ON THE LOW
SIDE AND DECREASED THE DURATION OF THE CONVECTION MENTION.
ISOLATED CONVECTION MAY LINGER SUNDAY MORNING ACROSS NORTHERN
WISCONSIN...BUT BY NOON THE H850 BOUNDARY IS PROGGED TO BE WELL
NORTH OF THE AREA. ANY PRECIPITATION CHANCES DURING THIS PERIOD
WILL TEND TO BE FOCUSED TOWARD NORTHWEST WISCONSIN TOWARD THE BEST
HEIGHT FALLS.

SUNDAY NIGHT INTO MONDAY...NEXT CHANCE OF CONVECTION ALONG A
TROUGH OR WEAKENING COLD FRONT. MOST MODEL RUNS DIMINISH THE PCPN
AS IT WORKS INTO EASTERN WISCONSIN CLOSER TO THE UPPER RIDGE WHICH
REMAINS OVER THE EASTERN GREAT LAKES AND MUCH OF THE EAST THIRD OF
THE COUNTRY. THE BRUNT OF THE CONVECTION WILL LIKELY TRACK OVER
NORTHWEST WISCONSIN AND ESPECIALLY OVER MINNESOTA NEAR THE
SURFACE AND 850 LOW LIFTING NORTHEAST.

MONDAY NIGHT...BROAD RRQ REGION OF THE UPPER JET FOCUSES THE
CONVECTION OVER THE CENTRAL PLAINS WHILE WHILE WEAK HIGH PRESSURE
BUILDS INTO THE REGION IN THE WAKE OF THE FROPA.  THE GFS WAS THE
ODD MODEL OUT WITH STALLING THE FRONT OVER THE AREA AND
CONTINUING CONVECTION MONDAY NIGHT.

MOST OF THE MODELS FOR THE REST OF NEXT WEEK...THE UPPER PATTERN
SHIFTS FROM A SOUTHWEST FLOW ALOFT TO A NEARLY ZONAL FLOW LATE IN
THE WEEK...BUT SOME AGREEMENT WITH MOST MODELS WITH RESPECT TO A
MORE ROBUST SHORT WAVE WITH RRQ UPPER JET REGION PASSING THROUGH
TOWARD MID WEEK. COULD SEE ANOTHER ROUND OF A SOAKING RAIN WITH
THE SURFACE FRONT AND H850 FRONT INTERACTING WITH THE UPPER JET.

TEMPERATURES WILL BE ABOVE NORMAL THROUGH TUESDAY...AND WELL ABOVE
NORMAL IN A STICKY AIR MASS SUNDAY ESPECIALLY IF THE CLOUDS CLEAR
OUT. TEMPERATURES COOLING BACK TO NEAR NORMAL LATER NEXT WEEK.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 634 PM CDT FRI AUG 22 2014

MOIST AIR AND LIGHT WINDS WILL ALLOW FOR DENSE FOG TO
FORM OVER MUCH OF THE AREA TONIGHT. MOST PLACES WILL HAVE IFR
CONDITIONS BY MIDNIGHT. CONDITIONS WILL GRADUALLY IMPROVE AFTER
13Z OR 14Z SATURDAY.
&&

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

$$

SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......RDM






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.