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000
FXUS63 KGRB 111807
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
107 PM CDT FRI JUL 11 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 416 AM CDT FRI JUL 11 2014

LATEST MSAS ANALYSIS SHOWING SURFACE HIGH PRESSURE NOW OVER
EASTERN LAKES. COLD FRONT EXTENDS FROM LOW NORTH OF LAKE WINNEPEG
SOUTH INTO THE CENTRAL PLAINS. AT 09Z RADAR SHOWING CONVECTIVE
COMPLEX BEGINNING TO CROSS THE MISSISSIPPI INTO NORTHWEST WI. TWO
OTHER AREAS OF CONVECTION EXTENDING WEST FROM AROUND LACROSSE INTO
NEBRASKA. NORTHERN AREA ASSOCIATED WITH SHORT WAVE CURRENTLY MOVING
THROUGH NORTHERN MN. WAA/850 WARM FRONT CONTRIBUTING TO STORM
DEVELOPMENT TO THE SOUTH.

CONCERNS THIS PERIOD ON POPS. SHORT WAVE TO EXIT THIS MORNING. WAA
CONTINUES TO BE FOCUSED SOUTH AND WEST OF CWA. HIGHEST POPS NORTH
THIS MORNING WITH SHORT WAVE. AFTER THAT FORCING AND INSTABILITY
OVER AREA LIMITED. BROUGHT POPS DOWN TO SLIGHTS...STAYING DRY IN
THE EAST FOR TODAY.

TONIGHT AND SATURDAY...STILL UNCERTAIN. BEST INSTABILITY TO BE
FOCUSED TO SOUTH. FLAT WESTERLY FLOW ALOFT...WITH MODELS NOT
SHOWING ANY SIG FEATURE TO KEY ON TONIGHT TO INITIATE CONVECTION.
HAVE STAYED WITH SMALL CHANCE POPS MAINLY SOUTH WITH THOUGHTS THAT
ACTIVITY DEVELOPING SOUTH COULD BRUSH REGION. COLD FRONT TO MOVE
INTO NORTHERN WI BY NOON SATURDAY...ACTING AS FEATURE FOR
DEVELOPMENT FOR STORMS OVER CWA. BEST CONDITIONS FOR SEVERE AGAIN
TO OUR SOUTH.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 416 AM CDT FRI JUL 11 2014

LITTLE CHANGE SHOWN BY THE MDLS FOR NEXT WEEK AS AN IMPRESSIVE UPR
RDG BUILDS ACROSS WRN NOAM AND A JUST AS IMPRESSIVE UPR TROF
SWINGS THRU ERN NOAM. AN UNSETTLED AND UNUSUALLY COLD PATTERN IS
SHAPING UP FOR NE WI FROM MON NGT THRU TUE NGT WITH MAX TEMPS ON
TUE 15 TO 20 DEGS BELOW NORMAL. RAIN CHCS TIED INITIALLY TO THE
PASSAGE OF A STRONG CDFNT...FOLLOWED BY INSTABILITY CHCS AS THE
COLD AIR ALOFT MOVES THRU. FORTUNATELY...THIS UPR TROF IS
PROGRESSIVE AND TEMPS SHOULD GRADUALLY RECOVER AS HI PRES AT THE
SFC ARRIVES AND BRINGS SUNSHINE BACK TO THE REGION.

INITIAL CDFNT TO CONT SLOWLY SAGGING SOUTH INTO NRN IL...THUS
ANTICIPATE A DIMINISHING PCPN TREND FOR SAT EVENING. THAT BEING
SAID...THE NEXT CDFNT TO ALREADY BE DROPPING SE TOWARD NW WI BY
DAYBREAK...THUS CANNOT COMPLETELY RULE OUT A FEW SHWRS FROM
RETURNING TO PARTS OF CNTRL WI LATE. MIN TEMPS TO RANGE FROM THE
UPR 50S NORTH TO THE MID 60S E-CNTRL WI.

THIS SECOND CDFNT DRIVES THRU NE WI ON SUNDAY...ALTHO THE MDLS
DISAGREE ON WHETHER THIS HAPPENS IN THE MORNING OR IN THE
AFTERNOON. THE LATER THE FROPA...THE HIGHER POTENTIAL OF SEEING A
STRONGER TSTM WITH THE STRONG SHEAR OVERHEAD. INSTABILITY IS
SERIOUSLY LACKING ACROSS WI (CAPES CAN`T REACH 1K J/KG...LI`S > 0)
THUS EVEN SIMPLE SHWR ACTIVITY TO BE AT A CHC ONLY. SUNDAY APPEARS
TO BE THE LAST DAY WHERE WE SEE NORMAL MAX TEMPS AS READINGS TOP
OUT FROM THE MID 70S TO LWR 80S.

MUCH LIKE SAT NGT...ANY LINGERING SHWR/TSTM CHCS TO BE TIED MAINLY
TO THE EVENING HOURS AS THE SECOND CDFNT DROPS FARTHER SE. THE
UNUSUALLY STRONG UPR TROF TO DROP SOUTH INTO NRN SECTIONS OF THE
GREAT LAKES AND UPR MS VALLEY LATER SUNDAY NGT AND BEGIN TO SEND A
VERY COOL AIR MASS TOWARD WI. 8H TEMPS TO BE IN THE SINGLE DIGITS
BY 12Z MON WHICH COULD SEND MIN TEMPS DOWN TO AROUND 50 DEGS NORTH
AND AROUND 60 DEGS E-CNTRL WI. THIS DEEP UPR TROF DIVES INTO THE
REST OF THE GREAT LAKES REGION ON MON WITH VERY COOL TEMPS ALOFT
(8H TEMPS DOWN TO AROUND +5C) AND VARIOUS PIECES OF SHORTWAVE
ENERGY ROTATING THRU THE TROF ITSELF. MID-LEVEL LAPSE RATES
STEEPEN TO 7 C/KM WHICH IS MORE THAN ENUF TO GENERATE SHWRS WHEN
COMBINED WITH DAYTIME HEATING. HAVE RAISED POPS OVER NRN WI TO
LOW-END LIKELY WITH HI-END CHC CATEGORIES ELSEWHERE. MAX TEMPS TO
BE HELD IN CHECK BY THE THICKENING CLOUDS/PCPN/COLD AIR ALOFT WITH
READINGS ONLY IN THE MID 60S N-CNTRL TO LWR 70S E-CNTRL WI.

EVEN WITH THE LOSS OF DAYTIME HEATING MON EVENING...THE COMBINATION
OF CYCLONIC FLOW AND INDIVIDUAL SHORTWAVES MOVING THRU THE UPR TROF
WL KEEP PCPN CHCS IN THE FCST THRU THE NGT. TUE WL BRING AN
AUTUMNAL FEEL TO THE AIR AS TEMPS WL STRUGGLE JUST TO REACH THE LWR
TO MID 60S...OR 15 TO 20 DEGS BELOW NORMAL. THESE VALUES WL
CHALLENGE ALL-TIME RECORD LOW MAX TEMPS FOR THAT DATE. EVEN THO THE
CRUX OF THE UPR TROF TO BE SITUATED TO OUR EAST ON TUE...THE AIR
MASS OVER WI TO STILL BE WELL BELOW CLIMATOLOGICAL NORMALS FOR
MID-JULY AND EXPECT TO SEE ANOTHER ROUND OF DIURNALLY-DRIVEN SHWR
ACTIVITY ACROSS THE ENTIRE FCST AREA.

FORTUNATELY...THE MEAN FLOW IS PROGRESSIVE ENUF TO SEND THIS UPR
TROF INTO SE CANADA TUE NGT...THO A LINGERING CYCLONIC FLOW REMAINS
THRU THE NGT. HI PRES IS THEN FCST TO BEGIN BUILDING ACROSS THE UPR
MS VALEY TOWARD WI ON WED. THE GFS ATTEMPS TO DEVELOP A FEW SHWRS
OVER THE SRN HALF OF WI DUE TO HANGING ON TO THE CYCLONIC FLOW/COOL
AIR ALOFT. WHILE THIS POSSIBILITY COULD EXIST...FEEL ANY PCPN WOULD
BE TOO ISOLATED TO ADD TO THE FCST AT THIS TIME. THIS WEAK HI PRES
TO PASS BY TO OUR SOUTH ON THU AND PROVIDE FOR A DECENT AMOUNT OF
SUNSHINE. TEMPS WL BEGIN A GRADUAL WARM-UP ON WED INTO THU WITH
READINGS REACHING THE MID TO UPR 70S ON THU.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 107 PM CDT FRI JUL 11 2014

VFR CIGS PREVAILED ACROSS ALL BUT THE FAR NORTHWEST
EXTENT OF THE FORECAST AREA AT MIDDAY. THERE WERE A FEW LIGHT
SHOWERS...MAINLY ACROSS FAR NORTHERN AND NORTHEAST WISCONSIN...BUT
THEY WERE ON THEIR WAY OUT ALONG WITH AN UPPER LEVEL SHORT WAVE.
FOG IS LIKELY TO DEVELOP DURING THE NIGHT AND CIGS WILL LOWER TO
MVFR AS A COLD FRONT APPROACHES THE AREA FROM THE NORTHWEST.
SHOWERS AND THUNDERSTORMS ARE POSSIBLE DURING THE LATE MORNING AND
THROUGHOUT THE AFTERNOON ON SATURDAY.
&&

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

$$

SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......MG