Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 260754
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
354 AM EDT SUN JUL 26 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM EDT SUN JUL 26 2015

EXPECT BUILDING 5H RIDGE HEIGHTS ACROSS THE REGION TODAY AS MID-
UPPER RIDGE AMPLIFIES OVER THE NORTHERN PLAINS. COULD SEE EVEN
SLIGHTLY WARMER TEMPS TODAY THAN YESTERDAY AS 8H TEMPS RISE TO 18-
20C IN A WSW FLOW. EXPECT INLAND TEMPS WELL INTO THE 80S WITH EVEN
LOWER 90S TEMPS POSSIBLE OVER TYPICAL WARM SPOT LOCATIONS LIKE
KENTON...BARAGA OR LA BRANCHE. STILL EXPECTING A LAKE BREEZE TO FORM
OFF OF LAKE SUPERIOR BY EARLY TO MID AFTERNOON ON...LOWERING TEMPS A
FEW DEGREES ALONG THE SHORELINE.

WITH RAP MODEL SHOWING MLCAPES 200-700 J/KG IN THE AFTERNOON ITS
POSSIBLE CONVERGENCE ALONG THE LAKE BREEZE BOUNDARY COULD MAYBE
TRIGGER AN ISOLD SHRA/TSRA. HOWEVER...THERE ARE PLENTY OF INHIBITING
FACTORS FOR SHRA/TSRA WHICH INCLUDE DRY AIR NOTED BELOW 800 MB OFF
RAP SNDGS...MID-LVL (700-500 MB) LAPSE RATES AROUND ONLY 6C/KM AND
MID-LVL Q-VECT DIV AS RIDGE HEIGHTS BUILD OVERHEAD. WL ONLY INCLUDE
SLIGHT CHC POPS FOR SHRA/TSRA ALONG LAKE BREEZE BOUNDARIES...MAINLY
CENTRAL AND EAST. WITH DEEP LAYER SHEAR LESS THAN 30 KTS WOULD NOT
EXPECT ANY SVR STORMS IF CONVECTION DOES INDEED FORM.

HIGH PRES OVER AREA SHOULD KEEP CONDITIONS DRY TONIGHT. THERE MAY BE
AN ISOLD SHRA/TSRA SNEAK IN OVER FAR NRN LAKE SUPERIOR FROM
CONVECTION FORMING TO THE NORTH WHERE MODELS DEPICT DEEPER MOISTURE
AND WEAK TO MODERATE WAA/ISENTROPIC ASCENT IN WESTERLY FLOW...BUT
UPPER MI SHOULD STAY DRY. MIN TEMPS WILL GENERALLY BE IN THE LOWER
TO MID 60S UNDER CLEAR TO PARTLY CLOUDY SKIES.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 419 PM EDT SAT JUL 25 2015

RIDGE ALOFT BUILDS FROM NORTHERN PLAINS TO UPPER GREAT LAKES MONDAY
AND MONDAY NIGHT. HIGH PRESSURE AT THE SFC SETTLES OVER EASTERN
CONUS WHILE STRONG TROUGH ALOFT DIGGING OVER ROCKIES HELPS DEVELOP
PRETTY STRONG SFC LOW PRESSURE SYSTEM FOR LATE JULY STANDARDS OVER
SCNTRL CANADA. GFS SHOWS A LOT OF LGT QPF FM WI INTO UPR MICHIGAN
SUNDAY NIGHT THROUGH MONDAY NIGHT...BUT ITS SOUNDINGS DO NOT REALLY
SUPPORT MUCH PRECIP WITH JUST A COUPLE THIN LAYERS OF MOISTURE AND
MINIMAL LIFT. PREFER THE DRIER IDEA FM THE NAM/ECMWF/GEM-REGIONAL.
ONLY SMALL EXCEPTION MAY BE A FEW SHRA LATE SUNDAY NIGHT INTO MONDAY
MORNING OVER EASTERN LK SUPERIOR AND FAR EAST CWA WITH MOISTURE FM
H8-H7 AND AT LEAST HUNDRED J/KG OF CAPE BASED WHEN LIFTING FM H85-
H8. PROBABLY JUST AN ACCAS FIELD WITH SPRINKLES OR SHRA. BEST CHANCE
WILL STAY OVER LK SUPERIOR INTO ONTARIO. LAKE BREEZES SHOULD FORM
BY AFTN AS THE HIGH PRESSURE AREA OVER THE EASTERN CONUS KEEPS WEAK
RIDGE BACK OVER THE GREAT LAKES. UNTIL LAKE BREEZES COME ONSHORE IN
THE AFTN...TEMPERATURES WILL WARM WELL INTO THE UPPER 80S OR LOW 90S
WITH SOUNDINGS MIXING TO AT LEAST H85 TEMPS UPWARDS OF +20C BY AFTN.
THUS...WHEN LAKE BREEZE COOLING OCCURS IN THE AFTN NEAR LK SUPERIOR
IT COULD HAVE SOME BITE TO IT...ESPECIALLY AT COPPER HARBOR/MARQUETTE
AND MUNISING WITH MORE OF AN ABRUPT WIND SHIFT EXPECTED.

AFTER A MILD/MUGGY NIGHT IN THE 60S MONDAY NIGHT...WARM FRONT TIED
TO THE SCNTRL CANADA LOW PRESSURE MOVES THROUGH TUESDAY AFTN INTO
TUESDAY EVENING WITH COLD FRONT CROSSING UPR MICHIGAN ON WEDNESDAY
MORNING. AS HAS OCCURRED RECENTLY...FEASIBLE THAT THERE MAY BE WEAKER
CONVECTIVELY INDUCED SHORTWAVES SLIDING OVER UPPER LAKES AS EARLY AS
TUESDAY MORNING AHEAD OF NORTHERN PLAINS TROUGH. ALL THE MODELS AT
LEAST HINT AT THIS POSSIBILITY BUT GFS IS STRONGEST WITH THESE
SHORTWAVE AND SHOWS LGT QPF INTO EASTERN CWA BY 00Z WEDNESDAY. THINK
GREATEST FOCUS FOR SHRA/TSRA ON TUESDAY WILL BE WEST AND SOUTHWEST OF
UPR MICHIGAN...NEARER THE TIGHTER GRADIENT OF MLCAPES OVER 2000 J/KG
AND WHERE MUCAPES ARE OVER 3000 J/KG. CAPPING LIKELY WILL BE AN ISSUE
FOR CONVECTION CHANCES ON TUESDAY AFTN OVER THE REGION AS LARGER
SCALE FORCING REMAINS STRONGEST WELL TO THE WEST OVER DAKOTAS AND
WITH STRONG INDICATION OF SHARPER WARMING CENTERED AT H8 PER NAM/GFS
SOUNDINGS. UNLESS THE INITIAL SHORTWAVES ARE STRONGER...PROBABLY WILL
HAVE TO WAIT UNTIL TUESDAY NIGHT FOR ANYTHING MORE THAN SLIGHT
CHANCES FOR SHRA/TSRA OVER UPR MICHIGAN. CANNOT COMPLETELY RULE OUT
ISOLD SHRA/TSRA TRYING TO MAKE INTO UPR MICHIGAN LATER IN THE DAY
THOUGH AS MEAN WINDS FM WSW WOULD ADVECT ANY POP-UP SHRA/TSRA TOWARD
SW CWA OUT OF MUCH HIGHER MUCAPE AREA TO THE SW. CAPPING MAY DIMINISH
THAT POTENTIAL THOUGH. SINCE THE SOUTHERLY FLOW INCREASES BTWN THE
PLAINS LOW AND DEPARTING HIGH...MAIN LAKE MODIFICATION WILL BE OFF LK
MICHIGAN ON TUESDAY. OTHERWISE...H85 TEMPS PUSHING PAST +20C SUPPORT
A HOT DAY AS LONG AS CLOUDS ARE NOT TOO DISRUPTIVE. MAY SEE MULTIPLE
READINGS IN THE LOWER 90S AWAY FM IMMEDIATE LK MICHIGAN SHORE.

COLD FRONT WORKS THROUGH LATER TUESDAY NIGHT INTO WEDNESDAY MORNING.
DETAILS FAR FM CERTAIN...BUT STRONG TO SEVERE STORMS SEEM POSSIBLE
WITH THE FROPA SOMEWHERE IN THE UPPER LAKES REGION...JUST NOT SURE
IT WILL BE OVER UPR MICHIGAN. INCREASING SW H85 JET DOES BRING
HIGHER MOISTURE CONTENT INTO UPPER LAKES JUST AHEAD OF THE FRONT
TUESDAY NIGHT WITH H85 DWPNTS OVER +15C BOOSTING PWATS TO OVER 2.0
INCHES. DEEP LAYER SHEAR IS MARGINAL TO START NIGHT...BUT DOES RISE
AFTER MIDNIGHT WITH APPROACH OF SHORTWAVE TROUGH. H85 JET VEERS MORE
WESTERLY LATE SO MIGHT SEE MORE CONCENTRATED AND STRONGER STORMS
STAY MAINLY SOUTH OF UPR MICHIGAN CLOSER TO PERSISTENT GRADIENT OF
HIGHER MLCAPE. STRONGEST H85 MOISTURE TRANSPORT IS ALSO FOCUSED
SOUTH OF UPR MICHIGAN. WARMEST TEMPS AT H8 POINT TO STRONGEST
CAPPING OCCURRING SOUTH THOUGH. KEPT WITH CONSENSUS HIGH CHANCE TO
LIKELY POPS ACROSS CWA...HIGHEST SOUTH...GIVEN STRONG FROPA/STRONGER
DYNAMICS INTERACTING WITH MUCAPES OVER 1000J/KG OVER UPR MICHIGAN.
DIRECTIONAL SHEAR AND INCREASING MID LEVEL WINDS OVERNIGHT COULD
SUPPORT HAIL POTENTIAL DESPITE FREEZING LEVELS NEARING 15KFT. MAYBE
BETTER WIND POTENTIAL AS 0-1KM SHEAR UP TO 20 KTS RUNS PERPENDICULAR
TO THE FRONT WHICH COULD LEAD TO LINE SEGMENTS/BOWING SEGMENTS AS
COLD POOLS WILL BE ABLE TO BALANCE OUT THE ENVIRONMENTAL SHEAR. WITH
SUCH HIGH FREEZING LEVELS...HEAVY RAIN WILL BE A BIG HAZARD AS WELL.

SHRA/TSRA WITH THE FRONT MOVES OUT QUICKLY ON WEDNESDAY MORNING.
COULD BE WINDY BY WEDNESDAY AFTN AS WINDS SHIFT WEST AS SFC LOW
DROPPING TO LESS THAN 995MB HEADS TOWARD HUDSON BAY. GFS FORECAST
SOUDNINGS SHOWED WELL MIX PROFILE ON THE LAKE AND OVER KEWEENAW WITH
WINDS WELL OVER 30 KTS. COULD SEE WINDS GUSTING TO 40-45 MPH OVER
THE MORE EXPOSED KEWEENAW. STILL BREEZY ON THURSDAY WITH LINGERING
TIGHT PRESSURE GRADIENT. NW WINDS WILL KEEP LK SUPERIOR SHORELINE
AREAS EAST OF MARQUETTE IN THE 60S. MID 70S MOST OTHER AREAS WITH
NEAR 80 DEGREES STILL POSSIBLE OVER FAR SCNTRL NEAR KMNM DUE TO
DOWNSLOPING WINDS.

ANOTHER SHORTWAVE TROUGH DROPS THROUGH LATE IN THE WEEK. TIMING IS
STILL UNCERTAIN...BUT SMALL CHANCES OF SHRA/TSRA SHOULD RESULT
FRIDAY AND FRIDAY NIGHT AS THE TROUGH SYNCHS UP WITH DAYTIME HEATING
AND MLCAPES NEARING 500 J/KG. DID NOT CHANGE CONSENSUS POPS. AFTER
THE BLO NORMAL DAY ON THURSDAY...HIGH TEMPS WILL BOUNCE BACK TO 80
DEGREES OR ABOVE FRIDAY THEN SLIP BACK INTO THE 70S ON SATURDAY
BEHIND THE TROUGH.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 203 AM EDT SUN JUL 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS HIGH PRESSURE
SHIFTS ACROSS LAKE MI OVERNIGHT...AND ACROSS LOWER MI SUNDAY
MORNING. THIS WILL KEEP A RIDGE ACROSS UPPER MI...WITH LIMITED
MOISTURE. SHRA/TSRA MAY DEVELOP ALONG LAKE BREEZE BOUNDARIES SUN
AFTERNOON THAT MAY AFFECT KSAW BUT PROBABILITY TOO LOW TO INCLUDE
MENTION AT THIS TIME.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 353 AM EDT SUN JUL 26 2015

WEAK PRES GRADIENT ACROSS THE REGION WILL KEEP WINDS GENERALLY LESS
THAN 20 KT THROUGH TUESDAY. LOW PRES DEVELOPING OVER S MANITOBA LATE
TUESDAY WILL BRING A TROUGH ACROSS LAKE SUPERIOR LATE TUESDAY NIGHT
AND A COLD FRONT ACROSS THE AREA ON WEDNESDAY. SOUTH WINDS AHEAD OF
THE FRONT COULD GUST NEAR 25 KNOTS OVER EASTERN LAKE SUPERIOR TUE
NIGHT WITH WESTERLY WINDS TO 30 KNOTS POSSIBLE WEDNESDAY INTO
WEDNESDAY IN THE WAKE OF THE COLD FRONT. HIGH PRES BUILDING OVER THE
CENTRAL PLAINS WILL PUSH A RIDGE OVER THE UPPER GREAT LAKES REGION
THURSDAY AND FRIDAY...WITH SLOWLY DIMINISHING WINDS THURSDAY.
&&

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

$$

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


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