Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 291143
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
743 AM EDT SAT AUG 29 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 553 AM EDT SAT AUG 29 2015

00Z RAOBS AND MODEL ANALYSIS INDICATES SHORTWAVE TROUGH CROSSING
UPPER GREAT LAKES THIS MORNING. WEAK LOW PRESSURE TROUGH IS OVER
NORTHERN PLAINS WHILE HIGH PRESSURE IS OVER MID ATLANTIC. WHEN SHIFT
STARTED CLUSTER OF SHRA/TSRA WERE DROPPING SOUTH OVER PORTIONS OF NW
ONTARIO INTO MINNESOTA ARROWHEAD. ADDITIONAL SHRA/TSRA WERE SLIDING
EASTWARD ACROSS ISLE ROYALE AND MUCH OF NORTHERN HALF OF LK
SUPERIOR. SPC MESOANALYSIS PAGE SHOWED 500-1000J/KG OF MUCAPE ACROSS
MINNESOTA AND LK SUPERIOR WITH EFFECTIVE SHEAR UP TO 30 KTS. 0-1KM
SHEAR VALUES WERE 25-30 KTS. ALL THAT REMAINS AT 09Z/5 AM EDT ARE A
FEW SHRA OVER EASTERN LK SUPERIOR AND DROPPING ACROSS NORTHWEST CWA.
STRONGER SHRA/TSRA BY FAR ARE OVER FAR WESTERN LK SUPERIOR CLOSEST
TO STEEPEST H7-H5 LAPSE RATES OVER 7.5C/KM AND ASSOCIATED MUCAPES
OVER 1000 J/KG. SINCE INSTABILITY DROPS OFF SIGNIFICANTLY FARTHER TO
EAST OVER LK SUPERIOR/UPR MICHIGAN...TSRA COVERAGE HAS GREATLY
DIMINISHED. FINALLY...ADDITIONAL AREA OF MAINLY SHRA IS OVER
NORTHERN LK MICHIGAN INTO NORTHERN LOWER MICHIGAN TIED TO SHORTWAVE
LIFTING THROUGH THAT AREA. COUPLE OF SHRA GRAZED FAR SOUTHEAST CWA
EARLIER TONIGHT. OVERALL THE CWA IS BEING SPLIT BY THESE TWO SYSTEMS.

CARRIED ISOLD SHRA MENTION THIS MORNING OVER WEST/NORTH CENTRAL AND
SOUTHEAST CWA AS LINGERING SHRA COULD IMPACT BOTH AREAS. TSRA
CHANCES SEEM SLIM THOUGH AS HIGHER 1-6KM ELEVATED MUCAPES STAY
ANCHORED OVER MINNESOTA. AFTER THESE SHRA DISIPPATE PER RADAR TRENDS
AND RAP/HRRR/NSSLWRF MODEL REFLECTIVITY...SCT LOW CLOUDS AND BKN MID
CLOUDS GRADUALLY DIMINISH THIS AFTN. SUPPOSE THERE IS A SMALL RISK
OF ADDITIONAL POP-UP SHRA/TSRA THIS AFTN AS LAKE BREEZES COULD LEAD
TO AT LEAST WEAK CONVERGENCE. MLCAPES REMAIN MINIMAL WHERE LAKE
BREEZE CONVERGENCE WOULD FIGURE TO BE STRONGEST OVER INTERIOR EAST
SO KEPT FORECAST DRY. H85 TEMPS SIMILAR TO WHAT OCCURED ON FRIDAY
BEFORE THE HEAT BEGINS TO BUILD LATER THIS WEEKEND INTO NEXT WEEK.
WENT WITH HIGHS PRETTY SIMILAR TO FRIDAY...UPR 70S OVER
INLAND/DOWNSLOPING AREAS OF WEST WITH LOW-MID 70S ELSEWHERE.

DRY WEATHER FOR TONIGHT AS HIGH PRESSURE RIDGE BEGINS TO BUILD
ALOFT. STEADY SW WIND BTWN HIGH OVER LOWER GREAT LAKES AND LOW
PRESSURE TROUGH OVER PLAINS SHOULD KEEP TEMPS LOWER 60S NEAR LK
SUPERIOR AND UPR 50S INLAND.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 328 AM EDT SAT AUG 29 2015

MODELS INDICATE RIDGE MOVING IN FROM THE NORTHERN PLAINS WILL
PROVIDE DRY WEATHER FOR THE EARLY PART OF NEXT WEEK....THEN A SERIES
OF WEAKER SHORTWAVES MOVING UP THE BACKSIDE OF RIDGE COULD BRING
SOME ISOLD TO SCT CONVECTION INTO THE UPPER GREAT LAKES BY MIDWEEK.
MODELS THEN SUGGEST MID-UPPER LEVEL RIDGE COULD REESTABLISH ITSELF
IN DEVELOPING BLOCKING PATTERN OVER NORTH AMERICA AND GREATLY
AMPLIFY INTO THE UPPER GREAT LAKES BY THE END OF NEXT WEEK/WEEKEND.
WELL ABOVE NORMAL TEMPS LOOK LIKE A GOOD BET THROUGH MUCH OF THE
WEEK WITH THE POTENTIAL FOR NEAR RECORD WARM TEMPS LATE IN THE WEEK.

SUN AND MON...MODELS SHOW NORTHERN PLAINS RIDGE MOVING INTO THE
UPPER GREAT LAKES IN RESPONSE TO BROAD TROUGH DEVELOPING OVER WRN
CANADA INTO THE PAC NW. WITH 8H TEMPS RISING TO AROUND 20C AND DEW
POINTS IN THE LOWER 60S IN A SW FLOW...EXPECT MUGGY CONDITIONS
WITH HIGH TEMPS BY MONDAY TO REACH INTO THE LOWER TO MID 80S.

TUE INTO THU...MODELS ADVERTISE A SERIES OF SHORTWAVES MOVING UP
BACKSIDE OF MID-UPPER LEVEL RIDGE AS RIDGE AXIS PUSHES EAST OF THE
WESTERN GREAT LAKES. SINCE TIMING OF THESE WEAKER SHORTWAVES IS
POORLY RESOLVED BY MODELS WILL CONTINUE TO INCLUDE ONLY LOW CHC POPS
FOR POSSIBLE CONVECTION FROM THESE FEATURES THROUGH THE PERIOD.

TOWARD END OF NEXT WEEK/WEEKEND...MODELS SUGGEST RIDGE MID-UPPER
LEVEL RIDGE WILL REESTABLISH ITSELF AND GREATLY AMPLIFY INTO THE
CENTRAL CONUS AND GREAT LAKES REGION AS A BLOCKING PATTERN DEVELOPS
WITH A BROAD TROUGH PERSISTING OVER WRN CANADA INTO THE U.S. WEST
COAST AND A CUT-OFF LOW DEVELOPING NEAR THE CANADIAN MARITIMES OVER
THE NORTH ATLANTIC.  WITH MANY OF THE MODELS FORECASTING 5H HEIGHTS
OF 590 DM OR GREATER AND 8H TEMPS GREATER THAN 20C...EXPECT HIGH
TEMPS WELL INTO THE 80S AND PERHAPS EVEN APPROACHING 90F OVER
PORTIONS OF THE WEST HALF OF UPPER MI. WOULD NOT BE SURPRISED TO SEE
A FEW RECORD HIGH TEMPS FALL FRI INTO SAT OVER THE WEST HALF OF THE
CWA. MUGGY CONDITIONS WILL CONTINUE WITH DEWPOINTS IN THE LOWER TO
MID 60S.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 742 AM EDT SAT AUG 29 2015

VFR CONDITIONS EXPECTED THROUGH TONIGHT. A FEW SHRA MAY YET AFFECT
KCMX THIS MORNING. OTHERWISE...SCT-BKN MID CLOUDS WILL GIVE WAY TO
CLEARING SKIES THIS AFTERNOON AND TONIGHT. LIGHT FOG COULD TRY TO
FORM LATE TONIGHT...ESPECIALLY AT KSAW. &&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 553 AM EDT SAT AUG 29 2015

EXPECT SW WINDS TO 25 KTS EARLY THIS MORNING. OTHERWISE...A
GENERALLY WEAK PRES GRADIENT WILL DOMINATE THE UPPER LAKES INTO
EARLY NEXT WEEK. ON MOST DAYS...WINDS WILL BE UNDER 15KT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...JLA
MARINE...JLA


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