Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 291915
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
315 PM 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 NIGHT THROUGH SATURDAY)
ISSUED AT 314 PM EDT SAT AUG 29 2015

MID-UPPER RIDGE MOVES OVER SUN NIGHT INTO MON...THEN SHIFTS E BEFORE
RE-ESTABLISHING AND BECOMING QUITE AMPLIFIED LATE IN THE WEEK.
SHORTWAVE ENERGY MOVING UP THE BACK SIDE OF THE RIDGE THROUGH MID
WEEK AND ROUNDING THE TOP OF THE RIDGE LATE IN THE WEEK MAY BRING
SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FROM TUE
ON...BUT PREDICTABILITY IS QUITE LOW AT THIS TIME.

TEMPERATURES ARE THE MORE SIGNIFICANT PART OF THE STORY AS A WARM
AIRMASS (850MB TEMPS 18-22C) WILL BE OVERHEAD THROUGH THE ENTIRE
LONG TERM PERIOD. EXPECT HIGHS TEMPS GENERALLY IN THE 80S TO MAYBE
AROUND 90...WHICH WILL BE ROUGHLY 10-20 DEGREES ABOVE NORMAL.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 142 PM EDT SAT AUG 29 2015

VFR TO HIGH MVFR FOG COULD TRY TO FORM LATE TONIGHT AT
KSAW...OTHERWISE VFR CONDITIONS WILL REMAIN THROUGH THE PERIOD.
EXPECT A LAKE BREEZE TO SLIDE NEAR SAW LATER THIS AFTERNOON. EXPECT
DIURNAL WINDS TO DIMINISH TO AROUND 5KTS OR LESS TONIGHT...BEFORE
PICKING UP AGAIN OUT OF THE S-SW SUNDAY.
&&

.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...TITUS
AVIATION...KF
MARINE...JLA


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