Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 241944
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
344 PM EDT SUN AUG 24 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EDT SUN AUG 24 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE ROCKIES
WITH DOWNSTREAM RIDGE EXTENDING N THRU THE GREAT LAKES. IN THE
TROF...A VIGOROUS SHORTWAVE WAS LIFTING THRU WY INTO ERN MT/FAR WRN
DAKOTAS. AHEAD OF THIS MAIN FEATURE...ANOTHER SHORTWAVE WAS LIFTING
THRU THE ERN DAKOTAS INTO MANITOBA. SHRA/TSRA HAVE BEEN LINED UP
WITH THIS WAVE ACROSS THE ERN DAKOTAS/WRN MN. LOW-LEVEL JET AHEAD OF
FEATURE HAS ALSO GENERATED SHRA FARTHER E IN NE MN INTO ADJACENT NRN
ONTARIO. CLOSER TO HOME...IT HAS BEEN A QUIET NIGHT. THERE HAVE BEEN
SOME SPRINKLES AT TIMES OVER THE W HALF OF UPPER MI AND PERHAPS A
BRIEF -SHRA OVER THE FAR W...PROBABLY TIED TO ERN EDGE OF LOW-LEVEL
JET. OTHERWISE...MOSTLY CLOUDY SKIES HAVE BEEN THE RULE OVER THE W
AND PARTLY CLOUDY E.

TODAY...SCT SPRINKLES/PERHAPS A -SHRA OVER THE W WILL END THIS
MORNING AS LOW-LEVEL JET LIFTS N. OTHERWISE...LOOKS LIKE A DRY DAY
IS ON THE WAY. APPROACHING COLD FRONT TODAY WILL REMAIN WELL W OF
UPPER MI WITH THE ROUGHLY N-S ORIENTED FRONT ONLY HALFWAY ACROSS MN
BY 00Z THIS EVENING. FCST SOUNDINGS ALSO SUGGEST A CAPPED
ENVIRONMENT WITH 850MB THERMAL RIDGE NOSING INTO THE AREA. SINCE
THERE IS ESSENTIALLY NO FORCING WITH MID/UPPER RIDGE HOLDING (NO
HEIGHT FALLS)...WILL CARRY DRY WEATHER THRU THE AFTN HRS. MAY BE
ABLE TO GET A FEW MORE BREAKS IN THE CLOUDS TODAY TO BOOST TEMPS
SOME. FCST REFLECTS THIS IDEA WITH MAX TEMPS MOSTLY IN THE UPPER
70S/LWR 80S. WILL BE A LITTLE COOLER IF CLOUDS CONTINUE TO BE MORE
PERSISTENT.

AS COLD FRONT PROGRESSES EASTWARD TONIGHT...HEIGHT FALLS SPREADING
OVERTOP ABUNDANT INSTABILITY (MLCAPE OF 1500-3000J/KG) SHOULD YIELD
RAPID TSTM DEVELOPMENT ALONG FRONT THIS EVENING IN MN. HIGH RES NAM
WINDOW...NCEP WRF ARW AND NMM AS WELL AS NSSL WRF ALL LOOK QUITE
REASONABLE WITH EXPECTATIONS. THE BIG QUESTION IS HOW THE STORMS
HOLD TOGETHER WHILE MOVING E INTO UPPER MI DURING THE NORMAL
NIGHTTIME DOWNWARD MLCAPE CYCLE. ALSO IN THIS CASE...DEEP LAYER
FORCING IS WEAK WHICH MAY FURTHER HASTEN A WEAKENING TREND DURING
THE NIGHT. AT THIS POINT...THE W HAS THE BEST CHC OF SEEING
CONVECTION GIVEN ARRIVAL EARLIER IN THE NIGHT. WITH DEEP LAYER SHEAR
INCREASING TO 30-40KT...STRONG STORMS AND PERHAPS AN ISOLD SVR ARE
POSSIBLE OVER THE FAR W IF STORMS ARRIVE EARLY ENOUGH BEFORE
INSTABILITY BEGINS DIMINISHING. WILL CARRY SHRA/TSRA CHANCES
EASTWARD DURING THE NIGHT...BUT WITH A GRADUAL LOWERING OF POPS.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 343 PM EDT SUN AUG 24 2014

A TRANSITION TO A COOLER AND MAINLY DRIER PATTERN WL BE IN STORE
THIS WEEK AS THE UPPER PATTERN TRANSITIONS TO A LOWER AMPLITUDE/MORE
ZONAL FLOW ALONG THE CNDN BORDER. OVER THE PAST COUPLE OF DAYS...
THERE HAVE BEEN SOME MODEL DIFFERENCES ON WHETHER THERE WOULD BE
SOME INTERACTION BTWN THIS NRN BRANCH FLOW AND A WEAKER SRN STREAM
IN THE CONUS. ALTHOUGH THE TREND THRU MID WEEK IS FOR A MORE ROBUST
AND DRIER NRN STREAM FLOW...LONGER TERM MODEL DIFFERENCES AND
RUN-TO-RUN INCONSISTENCIES RETURN FOR LATER IN THE WEEK.

MON NGT...THE CWA WL BE UNDER A SLOWLY VEERING WSW FLOW ALF TO THE S
OF VIGOROUS SHRTWV MOVING EWD THRU FAR NW ONTARIO. ALTHOUGH
ATTENDANT COLD FNT OVER THE SE CWA WL BE WEAKENING...GUIDANCE HINTS
A SECOND COLD FNT PUSHED ALONG BY A TRAILING UPR DISTURBANCE THAT IS
EMBEDDED IN THE VEERING FLOW ALF AND STREAKING ACRS NRN LK SUP/
ADJOINING ONTARIO WILL SURGE ACRS THE CWA. COMBO OF DRY AIR ALF AND
DIURNAL COOLING WL LIMIT PCPN CHCS ASSOCIATED WITH THIS SECONDARY
COLD FROPA...BUT WL INCLUDE SOME LO CHC POPS OVER MAINLY THE E HALF
OF THE CWA CLOSER TO TRACK OF TRAILING SHRTWV AND/OR WEAKENING
PRIMARY FNT/LINGERING HIER H85 DEWPTS NEAR 12-14C UNDER AREA OF
DEEP...ALBEIT RATHER WEAK DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE
SECOND SHRTWV. THE 12Z NAM IS MOST AGGRESSIVE WITH THE LLVL COOLING
BEHIND THE FROPA...SHOWING H85 TEMPS FALLING AS LO AS 5C OVER THE
FAR NW BY 12Z TUE. SO MIN TEMPS WL BE QUITE A BIT LOWER THAN
TNGT...ESPECIALLY OVER THE WRN CWA.

TUE...HI PRES AND MUCH DRIER AIR WITH PWAT FALLING AS LO AS 0.50 TO
1.00 INCH OVER THE S WL ARRIVE ACRS UPR MI. ALTHOUGH THERE MAY BE
SOME MID/HI CLDS OVER MAINLY THE SRN TIER ASSOCIATED WITH A SRN
STREAM WEAK DISTURBANCE PASSING THRU THE LOWER LKS...GUIDANCE HINTS
THE AIRMASS BLO H7 WL BE TOO DRY FOR ANY PCPN SO FAR N OF SFC BNDRY
IN THE LOWER LKS. THE ONE EXCEPTION WAS THE 00Z CNDN MODEL WHICH
INDICATED THE DEEPER MSTR TO THE S WOULD RETURN FARTHER N AHEAD OF
YET ANOTHER SHRTWV MOVING ALONG THE CNDN BORDER AND BRING SOME PCPN
TO THE SE CWA...BUT THE 12Z VERSION HAS BACKED OFF ON THIS WETTER
SCENARIO. H85 TEMPS VARYING FM ARND 8C OVER THE NW TO ARND 13C OVER
THE SCNTRL WL SUPPORT HI TEMPS FM THE 60S NEAR LK SUP TO NEAR 80
WITH SOME DOWNSLOPING INTO MENOMINEE COUNTY.

TUE NGT/WED...BULK OF THE LONGER TERM MODELS INDICATE A MORE WNW
CONFLUENT FLOW ALF AHEAD OF SHRTWV RDG EMBEDDED IN THE NRN STREAM
ALONG THE CNDN BORDER WL BRING HI PRES/DRY AIR TO THE UPR LKS AND
SUPPRESS DEEPER MSTR TO THE S. THE 12Z CNDN MODEL DOES HINT AT SOME
MID/HI CLDS LINGERING INTO WED ON THE NRN EDGE OF SHRTWV PASSING TO
THE S IN THE SRN STREAM...BUT ITS FCST LLVLS ARE TOO DRY FOR PCPN.
TUE NGT WL BE PLEASANTLY COOL AS H85 TEMPS ARE FCST TO BE ARND
8C/PWAT 0.50-0.75 INCH. WITH DRY AIR AND H85 TEMPS IN THE 8-10C
RANGE ON WED...EXPECT MOSUNNY CONDITIONS AND HI TEMPS IN THE LO 70S
OVER THE INTERIOR AWAY FM LK MODERATION.

WED NGT/THU...DRY HI PRES SHIFTING TO OVER SE ONTARIO IS FCST TO
DOMINATE AND BRING CONTINUED DRY WX TO UPR MI. AFTER ANOTHER COOL
NGT...TEMPS ON THU SHOULD BE A FEW DEGREES HIER THAN ON WED AS H85
TEMPS REBOUND TO 10-12C IN LGT RETURN SSW FLOW ARND DEPARTING SFC HI
PRES.

EXTENDED...SHRTWV/DEEPER MSTR ASSOCIATED WITH SRN BRANCH FLOW IS
FCST TO AT LEAST SKIRT THE SRN TIER OF THE CWA IN THE THU NGT TO FRI
NGT TIME PERIOD BEFORE A COLD FNT ASSOCIATED WITH A SHRTWV MOVING
THRU THE WNW NRN BRANCH FLOW CROSSES UPR MI ON SAT AND DRIVES THIS
MSTR TO THE S. GIVEN SOME TIMING/TRACK DIFFERENCES ON VARIOUS
SHRTWVS...WL CARRY NO MORE THAN THE CONSENSUS LO CHC POPS. DRY WX
SHOULD BE THE RULE NEXT SUN WITH HI PRES FOLLOWING THE SAT FROPA.
TEMPS DURING THIS TIME ARE LIKELY TO RUN AOB NORMAL.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 223 PM EDT SUN AUG 24 2014

WHILE DAYTIME HEATING HAS BEEN EFFECTIVE AT BRINGING HIGH END MVFR
TO VFR CONDITIONS TO IWD AND CMX. OTHERWISE...PERSISTENT S-SE WINDS
HAVE KEEP MVFR CLINGS GOING A BIT LONGER AT SAW. LOOK FOR SOME
IMPROVEMENT AT SAW THIS AFTERNOON. THE MAIN STORY FOR THIS TAF
PERIOD WILL BE THE NEARING COLD FRONT COLD FRONT APPROACHING FROM
THE W LATE THIS EVENING...BRINGING SHRA/TSRA TO W UPPER MI. KEPT A
MENTION OF VCTS AT KIWD...AS TS ACTIVITY SHOULD BE DIMINISHING
OVERNIGHT DUE TO DECREASING INSTABILITY. ONLY -SHRA HAVE BEEN
INCLUDED AT CMX FROM 06-10Z...NO TS. PLENTY OF MOISTURE WILL REMAIN
WITH UPSLOPE CONDITIONS BRINGING ANOTHER ROUND OF MAINLY MVFR
CEILINGS TO SAW OVERNIGHT. OTHERWISE...LOOK FOR SLOWLY IMPROVING
CONDITIONS W TO E ON MONDAY AS DRIER AIR WORKS IN FROM THE W BEHIND
THE EXITING COLD FRONT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 24 2014

FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU MON GIVEN
THE HUMID AIR MASS THAT CONTINUES TO LINGER OVER THE AREA. PASSAGE
OF A COLD FRONT MON WILL THEN WORK TO CLEAR OUT ANY FOG FROM W TO E
AS DRIER AIR FLOWS INTO THE UPPER LAKES. AHEAD OF THE COLD FRONT...E
TO SE WINDS WILL INCREASE SOME TODAY/TONIGHT. WINDS OF 15-25KT SHOULD
BE OBSERVED AT SOME OF THE HIGHER OBS PLATFORMS. IN THE WAKE OF THE
FRONT...WSW WINDS OF 15-25KT WILL DEVELOP OVER THE W HALF OF THE
LAKE ON MON. HIGH PRES WILL THEN SETTLE INTO THE UPPER LAKES LATE
TUE THRU THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...KC
AVIATION...KF
MARINE...ROLFSON




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