Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 280533
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
133 AM EDT THU MAY 28 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 416 PM EDT WED MAY 27 2015

WV IMAGERY AND RUC ANALYSIS INDICATED A SHORTWAVE EXITING TO THE
EAST OF LAKE SUPERIOR LEAVING WNW MID/UPPER LEVEL FLOW FROM S CNTRL
CANADA INTO THE NRN LAKES. A WEAK SHRTWV FROM WRN LAKE SUPERIOR INTO
NW WI COMBINED WITH MLCAPE VALUES FROM 500-1000 J/KG OVER AREAS
WHERE SUNSHINE HAS PREVAILED THIS AFTERNOON HAS TRIGGERED SOME
ISOLD/SCT SHRA/TSRA FROM YQT TO DLH AND NEAR THE WI BORDER FROM LNL
TO IMT.

LATE THIS AFTERNOON AND TONIGHT...RADAR TRENDS AND SHORT RANGE HIGH
RES MODELS SUGGEST THAT THE SHRA/TSRA WILL REMAIN NEAR THE WI
BORDER. SOME SHRA/TSRA MOVING ACROSS LAKE SUPERIOR ABOVE THE MARINE
LAYER MAY ALSO SURVIVE INTO NW UPPER MI THIS EVENING BUT WITH LESS
AVAILABLE MLCAPE AND THE LOSS OF DAYTIME HEATING...EXPECT THE
SHRA/TSRA TO DIMINISH. OTHERWISE...WITH COOLING BY LATE EVENING THE
REST OF THE PCPN WILL END.

WED...AS THE MID LEVEL TROUGH OVER THE ROCKIES EDGES TO THE EAST SW
FLOW WILL AGAIN DEVELOP FROM THE CNTRL PLAINS TO THE WRN LAKES.
EXPECT ENOUGH SUNSHINE TO PUSH TEMPS TO NEAR 80F OVER THE WEST HALF
RESULTING IN MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE. THE MODELS
SUGGEST THAT A WEAK SHRTWV MOVING INTO THE AREA WILL TRIGGER ANOTHER
ROUND OF ISOL/SCT TSRA OVER THE WEST DURING THE AFTERNOON. WITH 0-
6KM SHEAR VALUES INTO THE 30-35 KNOT RANGE...A FEW STRONGER STORMS
COULD DEVELOP WITH SMALL HAIL AND GUSTY WINDS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 412 PM EDT WED MAY 27 2015

PRIMARY WEATHER ISSUES IN THE LONG TERM ARE TSRA STRENGTH ON FRIDAY
AND MIN TEMPS/FREEZE POTENTIAL FOR SATURDAY NIGHT AND SUNDAY NIGHT.

SHORTWAVE RIDGE IS OVER UPPER GREAT LAKES ON THURSDAY EVENING WITH
BROAD TROUGH FM CNTRL CANADA BACK OVER THE WESTERN CONUS. ANY ISOLD
SHRA/TSRA ON THURSDAY AFTN SHOULD FADE AWAY WITH LOSS OF DAYTIME
HEATING AND MINUS ADDITIONAL LARGER SCALE LIFTING MECHANISM. ANOTHER
SMALL CHANCE OF SHRA/TSRA LATER AT NIGHT OVER THE WEST AHEAD OF
BETTER MOISTURE TRANSPORT OUT AHEAD OF LOW PRESSURE AND COLD FRONT
MOVING ACROSS THE NORTHERN PLAINS. SOME HINT OF WEAKER SHORTWAVE
TIED TO THAT MOISTURE TRANSPORT. IF THAT OCCURS...BETTER CHANCE FOR
ORGANIZED SHRA AND POSSIBLE TSRA LATE THU NIGHT INTO FRIDAY MORNING.

AS CENTRAL CANADA TROUGH ALOFT DROPS ACROSS MANITOBA AND NORTHERN
ONTARIO ON FRIDAY ASSOCIATED LOW PRESSURE AND SFC COLD FRONT MOVES
FROM NORTHERN PLAINS TO THE UPPER GREAT LAKES. DECENT AGREEMENT FM
THE MODELS THAT FROPA OCCURS FRIDAY AFTN. MAIN QUESTION REMAINS IN
HOW MUCH INSTABILITY BUILDS UP AHEAD OF THE FRONT...AND WOULD
CERTAINLY BE AFFECTED BY ANY SHRA/TSRA AROUND DURING THE MORNING
HOURS. OVERALL THERE IS DECENT AGREEMENT THAT MLCAPES WILL BE AT
LEAST 500J/KG AND MAY BE OVER 1000 J/KG BY TIME FRONT WORKS ACROSS
IN THE AFTN. GREATEST INSTABILITY IS LOCATED OVER WI...BUT IS
FORECAST TO EXPAND OVER PORTIONS OF CNTRL UPR MICHIGAN AHEAD OF THE
FRONT. DEEP LAYER SHEAR UP TO 35 KTS WOULD BE FAVORABLE FOR
ORGANIZED STORMS...BUT POTENTIAL WILL BE HELD DOWN IF MORE
WIDESPREAD SHRA AND TSRA ARE AROUND EARLIER IN THE DAY. MOISTURE
AVAILABILITY NOT AN ISSUE AS PERSISTENT H85-H7 MOISTURE TRANSPORT
BOOSTS PWATS OVER 1.5 INCHES ALONG AND AHEAD OF THE FRONT. FAIR TO
SAY IF THERE IS AT LEAST SOME INSOLATION ON FRIDAY...THERE WOULD BE
RISK OF AT LEAST STRONG STORMS DURING THE AFTN. SPC DAY3 RISK HAS
MARGINAL CATEGORY MAINLY SOUTH OF HERE INTO WHERE BETTER CHANCE OF
HIGHER INSTABILITY RESIDES. FRONT MOVES ACROSS ALL OF UPR MICHIGAN
AFTER MIDNIGHT FRIDAY NIGHT. IT WILL PROBABLY TAKE UNTIL THE FRONT
HAS EXITED BEFORE CHANCES OF RAIN ARE ELIMINATED DUE TO DEEP
MOISTURE PERSISTING EVEN BEHIND THE SFC FRONT AND POSSIBILITY OF
SHORTWAVES WORKING THROUGH ON EDGE OF LARGE SCALE TROUGH. POPS
HIGHEST FRIDAY WITH THIS FROPA.

CONFLUENCE ALOFT ON WESTERN EDGE OF TROUGH MOVING ACROSS NORTHERN
ONTARIO AND QUEBEC LEADS TO LARGE HIGH PRESSURE BUILDING IN ON
SATURDAY. CHILLY DAY FOR LATE MAY STANDARDS ON SATURDAY AS TEMPS
EVEN INLAND TOWARD WI BORDER MAY ONLY STRUGGLE INTO THE 50S DESPITE
GOOD DEAL OF SUNSHINE. GRADIENT ONSHORE WINDS NEAR LK SUPERIOR WILL
KEEP TEMPS THERE IN THE 40S. AIRMASS QUITE DRY WITH PWATS DROPPING
TO 0.25-0.35 INCHES BY SATURDAY NIGHT. LIGHT WINDS/CLEAR SKIES AND
DRY AIRMASS POINT TO STRONG RADIATIONAL COOLING AND WITH DWPNTS ON
SATURDAY BLO 30F...A FREEZE IS LIKELY ON SATURDAY NIGHT. LACK OF ANY
ONSHORE FLOW LATER SATURDAY NIGHT FAVORS EVEN SHORELINE AREAS NEAR
LK SUPERIOR AND MOST OF LK MICHIGAN FOR MIN TEMPS AT LEAST IN THE
LOWER 30S WITH STRONG FROST POSSIBILITY. WEAK EASTERLY WINDS ON
SOUTHERLY EDGE OF SFC HIGH COULD KEEP BAY OF GREEN BAY SHORE IN FAR
SCNTRL WITH THE WARMEST TEMPS OVER THE CWA. ANOTHER CHILLY DAY FOR
SUNDAY UNDER MOSTLY SUNNY SKIES. INLAND TEMPS NEAR 60 DEGREES WHICH
IS OVER 10 DEGREES BLO NORMAL. TEMPS ALONG LK SUPERIOR WILL BE
MAINLY IN THE 40S OR 50S. WENT ON LOW SIDE FOR TEMPS SUNDAY NIGHT
AND INCLUDED FROST MENTION AGAIN. SOME BIAS CORRECTED GUIDANCE
INDICATED MINS BACK TO AROUND 32 DEGREES WHICH SEEMS REASONABLE
AS RIDGE AND DRY AIRMASS LINGERS...ESPECIALLY CNTRAL AND EAST.

REST OF EXTENDED FEATURES A WARMING TREND. UPPER LEVEL FLOW FLATTENS
OUT IN WAKE OF THE TROUGH THIS WEEKEND. HIGH AT THE SFC SLOWLY MOVES
OFF TO THE EAST OVER NEW ENGLAND AND MID ATLANTIC PUTTING PLAINS AND
GREAT LAKES WITHIN RETURN FLOW. H85 TEMPS AS EARLY AS TUESDAY RISE
TO 14C...WHICH WOULD YIELD HIGHS WELL INTO THE 70S INLAND FROM THE
GREAT LAKES. MAY SEE SOME MID CLOUDS SPILL ACROSS UPR LAKES ON
TUESDAY DUE TO WARM AIR ADVECTION H85-H7. PROBABLY NOT MUCH RISK OF
SHRA THOUGH AS FORCING AND MOISTURE IS MARGINAL AT BEST. MAYBE BETTER
CHANCE OF SHRA/TSRA ON WEDNESDAY AS TROUGH ALOFT HEADS ACROSS
WESTERN CONUS. BETTER CHANCES PROBABLY STAY WEST YET CLOSER TO THE
SFC LOW OVER THE NORTHERN PLAINS. AS LONG AS SYSTEM DOES NOT SPEED
UP TO THE EAST...GOOD CHANCE THAT TEMPS MAY TOP OUT AROUND 80
DEGREES ON WEDNESDAY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 132 AM EDT THU MAY 28 2015

VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST. THERE REMAINS A
CONCERN FOR PATCHY FOG TO IMPACT ALL THREE SITES AS AS WINDS GO
LIGHT AND SKIES REMAIN CLEAR OVERNIGHT. THE BETTER POTENTIAL FOR LOW
CIGS AND FOG WILL BE AT KSAW AS LIGHT NE FLOW WILL BRING IN MOISTURE
OFF THE LAKE AND THUS HAVE BROUGHT IN MVFR VSBY THERE. LIGHT
EASTERLY FLOW OFF THE LAKE MAY ALSO REDUCE VSBY AT KCMX OVERNIGHT.
WITH RESIDUAL MOISTURE AT KIWD TO TO EARLIER RAINS FROM YESTERDAY
EVENING THEY ALSO HAVE A POSSIBILITY OF REDUCED VSBYS DUE TO FOG.
HAVE KEPT THESE RESTRICTIONS TO MVFR...BUT WOULD NOT DISCOUNT IFR
VSBYS DEVELOPING AT KSAW WITH THE UPSLOPE FLOW OFF THE LAKE. ONCE
THE SUN COMES UP...ANY FOG WILL QUICKLY BURN OFF. THERE IS A
POTENTIAL FOR LIGHT RAIN SHOWERS LATE IN THE AFTERNOON AT KIWD AND
KCMX BUT THE BETTER CHANCES FOR PCPN WILL HOLD OFF UNTIL 3Z WITH THE
APPROACH OF THE NEXT SYSTEM.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EDT WED MAY 27 2015WINDS ARE EXPECTED TO STAY AT OR BELOW 20 KNOTS FOR MOST
OF THIS FORECAST PERIOD WITH THE EXCEPTION OF FRI NIGHT INTO EARLY
SATURDAY WHERE THEY WILL INCREASE TO NEAR 30 KNOTS ACROSS EASTERN
LAKE SUPERIOR BEHIND A COLD FRONT MOVING THROUGH THE REGION. FOG
WILL LINGER THROUGH TONIGHT AND MAY BE DENSE AT TIMES. ADDITIONAL
FOG IS EXPECTED TO DEVELOP THURSDAY NIGHT AND FRIDAY AHEAD OF THE
NEXT LOW AND ASSOCIATED COLD FRONT.
&&

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

$$

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


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