Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 170858
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
358 AM CDT THU JUL 17 2014

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SYNOPSIS...
ISSUED AT 345 AM CDT THU JUL 17 2014

QUIET MID-SUMMER WEATHER WITH NEAR NORMAL TEMPERATURES AND LOW
HUMIDITIES FOR THE REST OF THE WORK WEEK.

THE LARGE SCALE PATTERN ACROSS NOAM CONTINUES TO DEAMPLIFY...WITH
THE MAIN WESTERLIES RECEDING NORTH INTO CANADA. A NEW LARGE SCALE
TROF POSN WL BE ESTABLISHED NR THE WEST COAST DURING THE WEEKEND.
THAT WL ALLOW RIDGING TO EXPAND ENEWD FM THE UPR ANTICYCLONE
ANCHORED IN THE 4 CORNERS REGION. ANOTHER UPR ANTICYCLONE WL
REMAIN OVER THE WRN ATL...LEAVING A WEAKNESS IN THE RIDGING OVER
THE GREAT LAKES RGN.

THE UPR PATTERN WL SUPPORT TEMPS CONTINUING TO SLOWLY WARM. THEY
SHOULD REACH NR NORMAL BY THE START OF THE WEEKEND...AND AT LEAST
SOMEWHAT ABV NORMAL EARLY NEXT WEEK. LITTLE PCPN IS EXPECTED
THROUGH THE WEEKEND AS WEAK UPR FLOW WL SUPPLY LITTLE FORCING AND
THE MAIN POOL OF MOIST UNSTABLE AIR WL REMAIN WELL TO OUR S.

THE WEAKNESS IN THE RIDGE OVER THE GREAT LAKES RGN WL PROBABLY
EVENTUALLY EVOLVE INTO A SIG LNGWV TROF. THE LATTER PORTION OF THE
MED RANGE MODEL RUNS ARE GIVING STG SUPPORT FOR THIS...AND FLIP
THE UPR PATTERN BACK TO THE WRN RIDGE/GREAT LAKES UPR TROF
CONFIGURATION WHICH HAS DOMINATED MUCH OF THIS SUMMER. THAT WL
MEAN A RETURN TO COOLER AND WETTER WX...THOUGH HOW QUICKLY THE CHG
OCCURS REMAINS UNCERTAIN.
&&

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 345 AM CDT THU JUL 17 2014

QUIET WX EXPECTED. A FEW OF THE MODELS GENERATED ISOLD SHRA
TDA... MAINLY OVER FAR NE WI...CLOSE TO THE ENHANCED LOW-LEVEL
CONVERGENCE ZONE OF THE DOUBLE LAKE SUPERIOR/LAKE MICHIGAN LAKE
BREEZE OVER UPPER MICHIGAN. THE NUMBER OF MODELS SUGGESTING LGT
PCPN FRI IS EVEN GREATER...THOUGH THERE ARE STILL QUITE A FEW THAT
REMAIN DRY.

EVEN ON THOSE MODELS PRODUCING PCPN TDA...FCST SOUNDINGS WERE NOT
IMPRESSIVE AND SUGGEST WARM TEMPS IN THE 600-700 MB LAYER WOULD
PROVIDE AN EFFECTIVE CAP. IN ADDITION...THE DEGREE OF INSTABILITY
PRESENT SEEMS OVERDONE. MIXING INTO DRIER AIR ALOFT TOOK SFC DWPTS
OVER IA AND IL DOWN YDA AFTN...AND THAT WAS DESPITE A MATURING
CORN CROP IN THOSE AREAS. EXPECT SIMILAR MIXING AND DRYING OVER
THE FCST AREA TDA AND PROBABLY AGAIN ON FRI. GIVEN THE REDUCED
LOW-LEVEL MOISTURE...THE RESULTING TEMP PROFILES JUST DO NOT SEEM
SUFFICIENT TO SUPPORT THE DEVELPMENT OF SHRA...SO WENT WITH DRY
FCST THROUGHOUT THE SHORT-TERM. WL PROBABLY GET CONSIDERABLE HIGH-
BASED CU THIS AFTN...AND TO A LESSER EXTENT FRI AFTN.

GIVEN THE DRY AIR...TOOK TEMPS UP A BIT BOTH DAYS...TO NR THE UPPER
EDGE OF THE MAX TEMP GUIDANCE SPECTRUM.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 345 AM CDT THU JUL 17 2014

LOW AMPLITUDE UPPER LEVEL FLOW IS EXPECTED OVER SOUTHERN CANADA
AND THE NORTHERN CONUS FOR THE START OF THE LONG TERM FORECAST.
THIS PATTERN SHOULD CONTINUE INTO EARLY NEXT WEEK BEFORE AN UPPER
LEVEL ANTICYCLONE BUILDS OVER THE ROCKIES AND HIGH PLAINS AND A
SIGNIFICANT TROUGH DEVELOPS INTO THE GREAT LAKES REGION.

THE 00Z GFS AND 00Z NAM BOTH PRODUCED SOME QPF IN WISCONSIN IN
THE WARM ADVECTION RETURN FLOW AROUND A SURFACE HIGH TO THE EAST
OF THE REGION LATE IN THE WEEK...WHILE THE 00Z ECMWF AND 00Z GEM
WERE DRY. BUT MODELS DID AGREE ON KEEPING THE RAIN...ASSOCIATED
WITH AN UPPER LEVEL SHORT WAVE AND A SURFACE LOW AND COLD
FRONT...NORTH OF THE AREA OVER THE WEEKEND.

THERE IS A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS THE
AREA ON MONDAY NIGHT...INCREASING TO CHANCE POPS FOR TUESDAY AND
WEDNESDAY...WITH THE APPROACH OF THE STRONG UPPER LEVEL SHORT
WAVE AND SURFACE LOW AND COLD FRONT.

A WARMING TREND IS EXPECTED THROUGH TUESDAY IN GENERALLY ZONAL
FLOW...WITH MOSTLY ABOVE NORMAL HIGH TEMPERATURES.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 345 AM CDT THU JUL 17 2014

OVERALL...GOOD FLIGHT CONDITIONS EXPECTED. THERE WL BE SOME PATCHY
FOG EARLY TDA...BUT THAT WL BURN OFF QUICKLY JUST AFTER SUNRISE.
ALTHOUGH CONSIDERABLE CU WL FORM TDA...IT SHOULD BE HIGH BASED.
&&

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

$$

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








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