Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 282011
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
411 PM EDT THU MAY 28 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 411 PM EDT THU MAY 28 2015

TROUGH ALOFT DIGGING OVER SCNTRL CANADA WITH EXTENSION OF THAT
TROUGH TO SW OVER THE US ROCKIES. WEAK SHORTWAVE WORKING ACROSS NW
ONTARIO. TAIL OF THIS WAVE SHOWS UP AS RATHER UNORGANIZED AREA OF
ENHANCED CLOUDS. THE WAVE COMBINED WITH DAYTIME HEATING AND MLCAPES
OVER 1000J/KG TO KICK OFF ISOLD-SCT SHRA AND TSRA OVER MOSTLY WEST
UPR MICHIGAN. THUS FAR...STORM INTENSITY HAS BEEN HELD DOWN BY
WEAKER LIFT/SHEAR ALOFT...MAYBE UP AROUND 30 KTS. STRONGER STORMS
THIS EVENING MAY STILL PRODUCE SMALL HAIL AND GUSTY WINDS AS DCAPES
NEAR 1000J/KG. OVERALL...THREAT OF SEVERE STORMS APPEARS LOWER THAN
YDY GIVEN WEAK LIFT/SHEAR. HEAVY DOWNPOURS MAY STILL OCCUR AS WELL
WHICH IF IT OCCURRED OVER ONE OF THE MORE ACTIVE RIVER BASINS /CRFM4
AND HRVM4/. ONCE THESE SHRA/TSRA RUN THEIR COURSE...EXPECT LULL AS
MAIN FORCING STAYS WELL TO THE WEST ALONG COLD FRONT OVER THE
NORTHERN PLAINS. AFTER THE PRECIP ENDS...MAIN ISSUE THROUGH THE
NIGHT LIKELY TURNS TO DENSE FOG NEAR LK MICHIGAN AS FOG OVER LK
MICHIGAN COMES IN ON SOUTHERLY FLOW. PUT A DENSE FOG ADVY OUT OVER
THE NEARSHORE WATERS...BUT COVERAGE ON LAND WILL MORE PATCHY SO NO
ADVY THERE.

ATTN LATER TONIGHT SHIFTS TO SHORTWAVE THAT IS CURRENTLY LIFTING OUT
OF OK/KS. MODELS INSISTENT THAT THE SHORTWAVE LIFTS TOWARD UPR LAKES
TOWARD MORNING...09Z-12Z AT THE WI BORDER AND SHORTLY AFT 12Z CLOSER
TO LK SUPERIOR. NOT SURE HOW MUCH TSRA WILL TIE INTO THESE SHRA AS
ELEVATED MUCAPE VALUES STAY BLO 500J/KG...BUT WILL KEEP CHANCES OF
TSRA GOING. LIKELY MORE OF WIDESPREAD RAIN WITH EMBEDDED TSRA SO NOT
EXPECTING SVR WITH THIS FIRST BATCH OF RAIN IN THE MORNING. RAIN MAY
BE HEAVY THOUGH AS PWATS SURGE ABOVE 1.5 INCHES WITH H85 DWPNTS OVER
+10C. WILL HAVE TO WATCH THE MICHIGAMME RIVER BASIN NEAR CRYSTAL
FALLS AND ALSO THE CHOCOLAY RIVER BASIN NEAR HARVEY AS RECENT HEAVY
RAINFALL IN THESE AREAS HAS RESULTED IN RIVER LEVELS NEAR BANKFULL.

ANOTHER SHORTWAVE MOVES THROUGH IN THE AFTN AS COLD FRONT APPROACHES
AS SHOWING UP WITH SECONDARY SURGE OF DEEP LAYER Q-VECTOR
CONVERGENCE. WIDESPREAD RAIN/CLOUDS IN THE MORNING WILL MAKE FOR
QUESTIONS REGARDING HOW MUCH INSTABILITY CAN BUILD UP MID-LATE AFTN
FOR THE NEXT SHORTWAVE AND COLD FRONT TO WORK ON. GIVEN PERSISTENT
THETA-E ADVECTION ALONG AND AHEAD OF THE FRONT IN THE AFTN...EXPECT
GOOD COVERAGE OF SHRA...ESPECIALLY OVER SOUTHERN CWA. STILL AGREE
WITH SPC DAY2 RISK WHICH KEEPS BETTER CHANCES OF SEVERE SOUTH OF CWA
MORE INTO THE GREATER INSTABILITY. BASED ON CONVERGENT LOW-LEVEL
FLOW AHEAD OF THE COLD FRONT...MAY SEE STRONG STORMS TRY TO MOVE
BACK INTO SCNTRL CWA /IMT/MNM/ESC/ LATE IN THE AFTN. ONE MORE WARMER
DAY WITH HIGHS INTO THE 70S MOST AREAS. ANY SUNSHINE IN THE AFTN
WOULD RESULT IN TEMPS UP NEAR 80 DEGREES.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 439 AM EDT THU MAY 28 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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 148 PM EDT THU MAY 28 2015

A WARM FRONT WILL PUSH THROUGH THIS AFTERNOON...LEADING TO SCATTERED
SHOWERS AND POSSIBLY THUNDERSTORMS OVER MAINLY WESTERN UPPER
MICHIGAN. HAVE INCLUDED -SHRA AT KCMX AND VCNTY OF KSAW. LEFT
THUNDER OUT THOUGH GIVEN UNCERTAINTY IN THUNDER COVERAGE. ANY SHRA
DIMINISH THIS EVENING...THEN MORE SHOWERS AND POSSIBLE TSRA WILL
MOVE BACK OVER ALL TAF SITES ON FRIDAY MORNING. WARM FRONT MOVING
THROUGH BY THIS EVENING WILL SET UP A LOW-LEVEL JET TONIGHT...SO
HAVE INCLUDED LOW-LEVEL WIND SHEAR AT ALL TAF SITES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 411 PM EDT THU MAY 28 2015

WINDS ARE EXPECTED TO STAY AT OR BELOW 20 KNOTS FOR MOST OF THIS
FORECAST PERIOD WITH THE EXCEPTION OF TONIGHT INTO FRIDAY MORNING
OVER FAR EASTERN LK SUPERIOR WITH STRONGER SOUTH WINDS TO 30 KTS
POSSIBLE...THEN AGAIN FRI NIGHT INTO EARLY SATURDAY WHERE THEY MAY
INCREASE TO NEAR 30 KNOTS ACROSS EASTERN LAKE SUPERIOR BEHIND A COLD
FRONT MOVING THROUGH THE REGION. FOG WILL LINGER THROUGH INTO FRIDAY
NIGHT AND WILL BE DENSE AT TIMES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  DENSE FOG ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LSZ245>247.

LAKE MICHIGAN...
  DENSE FOG ADVISORY UNTIL 8 AM EDT FRIDAY FOR LMZ248-250.

&&

$$

SHORT TERM...JLA
LONG TERM...07
AVIATION...JLA
MARINE...JLA



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