Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 071957
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
357 PM EDT TUE JUL 7 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE JUL 7 2015

WV IMAGERY AND RAP ANALYSIS INDICATED DRYING ACROSS THE WRN LAKES AS
MID/UPPER LEVEL TROUGH FROM JAMES BAY TO NRN LOWER MI SLIDES OFF TO
THE EAST. AT THE SFC...HIGH PRES FROM THE NRN PLAINS TO THE UPPER MS
VALLEY WAS BUILDING INTO THE NRN LAKES RESULTING IN ACYC NRLY FLOW
FROM LAKE SUPERIOR THROUGH UPPER MI. THIS HAS BROUGHT COOL AIR INTO
THE AREA WITH READINGS RANGING FROM AROUND 60 NEAR LAKE SUPERIOR TO
THE MID 60S SOUTH AND DEWPOINTS IN THE MID 40S. VIS LOOP SHOWED AN
EXTENSIVE CU FIELD OVER THE INLAND WEST HALF BU MAINLY CLEAR SKIES
OVER THE EAST.

TONIGHT...HIGH PRES BUILDS OVER THE AREA WITH LIGHT WINDS AND CLEAR
SKIES WILLL BRING VERY FAVORABLE RADIATIONAL COOLING CONDITIONS AS
PWAT VALUES DROP TO AROUND 0.4 INCH. EXPECT TEMPS TOWARD THE LOWER
END OF GUIDANCE WITH MIN READINGS INTO THE UPPER 30S OVER THE
INTERIOR WEST HALF WHERE A MENTION OF PATCHY FROST WAS INCLUDED.

WED...SUNSHINE WITH FCST MIXING HEIGHTS TO AROUND 800 MB WILL
SUPPORT MAX READINGS INTO THE LOWER 70S AS 850 MB TEMPS CLIMB TO
AROUND 10C. LAKE BREEZES WILL BRING COOLER AIR INTO LOCATIONS NEAR
THE GREAT LAKES.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 508 AM EDT TUE JUL 7 2015

DURING THE LONG TERM...GFS/ECMWF ARE IN GOOD AGREEMENT ON THE
EVOLUTION OF THE PATTERN ACROSS N AMERICA. TROF ENCOMPASSING MUCH OF
CNTRL CANADA (FAIRLY NOTABLE NEGATIVE HEIGHT ANOMALIES FOR JULY)
WILL EXTEND WEAKLY INTO THE NCNTRL CONUS/GREAT LAKES FOR THE NEXT
COUPLE OF DAYS. THEN...IT WILL WEAKEN/LIFT N DURING THE LAST HALF OF
THE WEEK AS HEIGHTS RISE OVER THE ERN CONUS. THE RISING HEIGHTS WILL
LEAD TO THE DEVELOPMENT OF A CLOSED 500MB HIGH OVER THE SE CONUS
WHICH WILL THEN RETROGRADE QUICKLY AND EVOLVE INTO A RIDGE EXTENDING
FROM THE SRN ROCKIES TO THE NW TERRITORIES BY MON. THIS WILL FORCE
INCREASED TROFFING INTO SE CANADA/THE GREAT LAKES AND NEW ENGLAND
EARLY NEXT WEEK. FOR UPPER MI...THESE LARGE SCALE CHANGES WILL MEAN
BLO NORMAL TEMPS INITIALLY WILL TREND GRADUALLY UP TO SLIGHTLY ABOVE
NORMAL LATE WEEK INTO THE WEEKEND BEFORE COOLING AGAIN EARLY NEXT
WEEK. COULD BE QUITE COOL (FOR JULY STANDARDS) FOR A TIME NEXT WEEK
DEPENDING ON LONGITUDE OF WRN RIDGE AXIS AND HOW AMPLIFIED THE RIDGE
ACTUALLY BECOMES. AS FOR PCPN...THE NEXT FEW DAYS WILL BE DRY WITH
ANY SHORTWAVE ENERGY PASSING BY TO THE N OF HERE. AS THE FLOW TURNS
WSW LATE WEEK INTO THE WEEKEND...SHORTWAVES ROUNDING THE HIGH/RIDGE
RETROGRADING FROM THE SE CONUS WILL BRING THE POTENTIAL FOR
SHRA/TSRA AT TIMES OVER THE WEEKEND...BUT WIDESPREAD PCPN LOOKS
UNLIKELY ATTM.

ON WED/THU...A FAIRLY DEEP MID LEVEL LOW WILL BE DRIFTING ACROSS
HUDSON BAY. AS THIS OCCURS...A SHORTWAVE WILL SWING AROUND THE LOW
AND ACROSS NRN ONTARIO. ASSOCIATED COLD FRONT WILL MOVE ACROSS NRN
ONTARIO AND NW MN WED. SCT CONVECTION SHOULD ACCOMPANY THE FRONT
WITHIN NARROW BAND OF INSTABIILTY...BUT WITH FRONT WELL TO THE NW OF
HERE WED...PCPN IS NOT A CONCERN. AS THE SHORTWAVE CONTINUES TO
SHIFT E WED NIGHT/THU...HEIGHTS BEGIN TO RISE ACROSS THE UPPER GREAT
LAKES...RESULTING IN APPROACHING FRONT WASHING OUT WITH TIME.
COMBINED WITH LOSS OF INSTABILITY ALONG FRONT...DO NOT ANTICIPATE
ANY PCPN WED NIGHT/THU. IF ANYTHING...ISLE ROYALE MIGHT GET CLIPPED
BY AN ISOLD SHRA.

HEIGHTS CONTINUE TO RISE ON FRI...SUPPORTING A CONTINUATION OF DRY
WEATHER. THE GFS AND GEM DO INDICATE A SHORTWAVE LIFTING ACROSS THE
PLAINS TO THE UPPER GREAT LAKES BY LATE IN THE DAY. GIVEN THE
WEAKENING OF THE SHORTWAVE AS IT MOVES THRU THE BUILDING RIDGE
AXIS...NOT EXPECTING SUFFICIENT MOISTURE/INSTABILITY TRANSPORT TO
PROVIDE A RISK OF PCPN HERE ON FRI.

AS MENTIONED EARLIER...SHORTWAVES ROUNDING THE HIGH/RIDGE
RETROGRADING FROM THE SE CONUS WILL BRING THE POTENTIAL FOR
SHRA/TSRA OVER THE WEEKEND. PATTERN LOOKS FAVORABLE FOR TYPICAL
SUMMERTIME TSTM CLUSTERS RUNNING ALONG THE EDGE OF MID LEVEL CAP AND
EDGE OF STRONG INSTABILITY. WITH UNCERTAINTY IN THE TRACK OF THE
WAVES AND HOW AGGRESSIVELY INSTABILITY BUILDS TOWARD THE UPPER
LAKES...FCST WILL SHOW MOSTLY LOWER RANGE CHC POPS. 00Z ECMWF
TRENDED TOWARD KEEPING MUCH OF THE SHORTWAVE ENERGY MORE
SUPPRESSED...RESULTING IN WHAT WOULD PROBABLY BE A DRY WEEKEND HERE.
WILL WAIT TO SEE IF LATER MODEL RUNS MAINTAIN THIS IDEA AND IF OTHER
MODELS TREND IN THAT DIRECTION BEFORE DOWNPLAYING WEEKEND PCPN
CHANCES.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 149 PM EDT TUE JUL 7 2015

HIGH PRESSURE MOVING IN THIS AFTERNOON WILL BRING CLEARING SKIES
THIS AFTEROON AT SAW. OTHERWISE...VFR CONDITIONS WILL PREVAIL
THROUGH THE FCST PERIOD. EXPECT A PERIOD OF NORTH WINDS TO NEAR 20
KNOTS THIS AFTN AT KSAW. OTHERWISE...WINDS WILL BE LIGHT THROUGH
TONIGHT AT THE TAF SITES.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 AM EDT TUE JUL 7 2015

N-NW WINDS UP TO 25 KTS EXPECTED THIS MORNING IN WAKE OF THE COLD
FRONT THAT MOVED THROUGH LAST EVENING...THEN WINDS WILL BEGIN TO
DIMINISH THIS AFTN EXCEPT WSW WINDS MAY KICK UP TO 20 KTS BRIEFLY
OVER MAINLY NORTHERN SECTIONS TOWARD ISLE ROYALE. AS HIGH PRESSURE
MOVES OVERHEAD TONIGHT...WINDS WILL DIMINISH BLO 20 KTS. THE HIGH
WILL GENERALLY REMAIN OVER THE GREAT LAKES REGION THROUGH
SATURDAY...RESULTING IN WINDS REMAINING MOSTLY BLO 15 KTS. WINDS MAY
INCREASE A BIT WED NIGHT IN RESPONSE TO A LOW PRES TROF CROSSING NRN
ONTARIO.
&&

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

$$

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


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