Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 191742
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1242 PM CDT SAT JUL 19 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SYNOPSIS...
ISSUED AT 410 AM CDT SAT JUL 19 2014

TEMPERATURES AND HUMIDITIES CONTINUING TO CREEP UPWARD THE NEXT
FEW DAYS. GENERALLY QUIET THROUGH THE WEEKEND...THOUGH A FEW
SHOWERS COULD MAKE INTO NORTH-CENTRAL WISCOMSIN AT TIMES.

LARGE SCALE UPR TROF WL DEVELOP NR THE WEST COAST THE NEXT FEW
DAYS...ALLOWING INCREASED RIDGING DOWNSTREAM OVER THE CONUS. A
WEAKNESS IN THE RIDGE BETWEEN ANTICYCLONE CENTERS OVER THE DESERT
SW AND THE WRN ATL WL ALLOW SOME TROFFING TO DEVELOP OVER THE ERN
CONUS MID-WEEK. THEN AFTER A BRIEF FLATTENING OF THE FLOW LATE IN
THE WEEK...ANOTHER AMPLIFICATION OF THE PATTERN WL OCCUR WITH THE
ERN TROF DEVELOPING INTO A MAJOR LNGWV FEATURE.

OTHER THAN POSSIBLY DUE TO SOME VARIATIONS BECAUSE OF CLOUD
COVER...THE AIR MASS ACRS THE AREA WL CONT TO WARM...WITH TEMPS
CREEPING UPWARD EACH DAY FOR THE FIRST HALF OF THE FCST PERIOD.
PERSISTENT SLY FLOW WL ALSO BRING HIGH DWPTS BACK INTO THE
AREA...SO IT WL BEGIN TO FEEL HUMID AS WELL. ONCE THE ERN NOAM
TROF BEGINS TO REFORM MID-WEEK...TEMPS WL RETURN CLOSER TO
SEASONAL NORMALS AND THE HUMID CONDITIONS WL EASE AS WELL.

A SERIES OF FRONTAL SYSTEMS WL CROSS THE PLAINS AND THEN WIPE OUT
AS THEY APPROACH THE WRN GREAT LAKES RGN THE NEXT FEW DAYS. THIS WL
LEAD TO SOME OPPORTUNITY FOR PCPN OVER MAINLY THE NW PART OF THE
FCST AREA THROUGH THE WEEKEND. BUT A MUCH BETTER CHC FOR
WIDESPREAD SIG PCPN IS EXPECTED DURING THE MIDDLE PART OF NEXT WK
AS A STRONGER WX SYSTEM CROSSES THE AREA.
&&

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 410 AM CDT SAT JUL 19 2014

GIST OF PREV FCST REMAINS INTACT WITH THIS ISSUANCE...WITH ONLY
MINOR TWEAKS TO PCPN TIMING AND TEMPS. PLAINS FRONTAL SYSTEM WL BE
APPROACHING WRN WI LATE THIS AFTN...BUT IS EXPECTED TO DISSIPATE
BEFORE REACHING THE FCST AREA. BEST UPR SUPPORT WAS TURNING NE AND
AND WL LIFT OUT WELL W OF THE AREA AS WELL. BUT TAIL OF THE SHRTWV
WL BRUSH N-C WI ARND PEAK HEATING. GIVEN THAT AND THE INCREASED
MOISTURE OVER THE PAST COUPLE DAYS...OPTED TO KEEP MENTION OF PCPN
FOR N-C WI. DIMINISHED POPS AS THEY SPREAD EWD ACRS THE N TNGT.
SHEAR WL BE WEAK AND INSTABILITY MARGINAL...SO NOT EXPECTING SVR.

A REPEAT OF THE ABV SCENARIO WITH FRONTAL SYSTEM DYING TO OUR W
AND WEAKENING UPPER SUPPORT CROSSING THE AREA IS SET TO PLAY OUT
SUN/SUN NGT. BUT SYSTEM SEEMED FAR ENOUGH W ON SUN TO KEEP SUN
DRY.

LARGE AREA OF MID CLDS OVER C/N-C WI EARLY THIS MORNING...WITH
CONVECTIVE DEBRIS W OF THAT. THOSE CLDS COMBINED WITH SOME AFTN CU
WL LIMIT SUNSHINE TO LESS THAN RECEIVED YDA. SO STUCK WITH MAXES
CLOSE TO YDA IN THE W. FEWER CLDS SHOULD ALLOW A COUPLE DEG OF
WARMING IN THE E. FEWER CLDS SUN SHOULD ALLOW A FEW DEG OF
WARMING...INTO THE LOWER TO MIDDLE 80S MOST AREAS. BUT LAKE
MICHIGAN WATERS ARE STILL QUITE COLD...AND GRADIENT SLY FLOW UP
THE LENGTH OF LAKE MICHIGAN IS GOING TO KEEP THE CLAMPS ON TEMPS
AT THE LAKESHORE. THE MARINE SENSOR AT THE KEWAUNEE LAKESHORE
COULD NOT BREAK 60F YESTERDAY. ITS HARD TO SEE HOW THAT AREA WL
GET OUT OF THE 60S TDA OR TOMORROW. THE WATERS OFF DOOR COUNTY ARE
A LITTLE WARMER...SO THAT AREA PROBABLY WON/T BE QUITE AS COOL.
COULD SEE SOME PATHCY FOG OVER LAKE AT TIMES...ESP ONCE THE HIGHER
DWPTS ARRIVE IN THE AREA SUN.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 410 AM CDT SAT JUL 19 2014

AS A TROUGH DIGS ACROSS THE WEST COAST OF THE CONTINENT...THE GFS
ENSEMBLE MEAN SHOWS SUB-TROPICAL RIDGING DOWNSTREAM OVER THE
CENTRAL CONUS WHICH WILL BRING A PROLONGED PERIOD OF SUMMER LIKE
TEMPS AND HUMIDITY TO THE REGION FOR SEVERAL DAYS EARLY NEXT WEEK.
THE MEDIUM RANGE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
LARGE SCALE PATTERN SO A BLEND OF THE ECMWF AND GFS SHOULD
SUFFICE.

SUNDAY NIGHT THROUGH MONDAY NIGHT...MID-LEVEL RIDGING WILL BE
BUILDING ACROSS THE WESTERN GREAT LAKES SUNDAY NIGHT. AS THIS
OCCURS...LOW LEVEL THETAE ADVECTION WILL BE PUSHING IN FROM THE
WEST LATE IN THE NIGHT. DECENT MOISTURE TRANSPORT AND INCREASING
ELEVATED INSTABILITY WILL LEAD TO A CHANCE OF SHOWERS AND STORMS
GENERALLY AFTER MIDNIGHT THOUGH IT MAY REACH NORTH-CENTRAL
WISCONSIN SHORTLY BEFORE THAT. EFFECTIVE BULK SHEAR VALUES ARE
RELATIVELY LOW IN THE 20 TO 25 KTS RANGE SO SEVERE CHANCES LOOK
LOW. CLOUDS LOOK TO HANG ON IN THE WARM ADVECTION ZONE MONDAY
MORNING. WOULD NOT BE SURPRISED TO SEE A SHOWER AND STORM OVER
EASTERN WISCONSIN BUT WILL LEAVE IT OUT FOR NOW FOR BLENDING
PURPOSES. THEN DECREASING CLOUDS AND TURNING HOT AND HUMID. HIGHS
IN THE MID TO UPPER 80S. THEN A SHORTWAVE WILL MOVE INTO THE
NORTHERN MISSISSIPPI VALLEY LATE MONDAY NIGHT WITH A WARM FRONT
DEVELOPING OVER FAR NORTHERN WISCONSIN. AS A RESULT...THE CHANCE
OF SHOWERS AND STORMS WILL INCREASE LATE.

REST OF THE FORECAST...THE DYNAMIC LOOKING SHORTWAVE WILL MOVE
ACROSS THE REGION TUESDAY AND TUESDAY NIGHT. SOME QUESTION MARKS
IN REGARDS TO THE AMOUNT OF SHEAR THAT WILL BE PRESENT BUT SHOULD
HAVE AMPLE INSTABILITY AND FORCING. WILL CONTINUE TO HIGHLIGHT
THIS PERIOD IN THE HWO FOR THE POSSIBILITY OF SEVERE WEATHER. THE
SHORTWAVE WILL BE PULLING OUT ON WEDNESDAY BUT A FEW SHOWERS COULD
LINGER INTO THE MORNING. THEN TURNING COOLER AND LESS HUMID BEHIND
THE FRONT FOR LATE IN THE WORK WEEK.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1238 PM CDT SAT JUL 19 2014

OVERALL...VFR CONDITIONS TO CONTINUE INTO SUNDAY FOR MUCH OF THE
AREA. EXCEPTION WOULD BE WITH POSSIBLE SHOWER DEVELOPMENT MAINLY
NORTH CENTRAL BUT ALSO ALONG LAKE BREEZE THIS AFTERNOON. &&

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

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......MPC
AVIATION.......TE






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