Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 261749
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1249 PM EST MON JAN 26 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EST MON JAN 26 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
OVER CENTRAL NAMERICA BTWN A HI AMPLITUDE RDG OVER THE W AND A DEEP
TROF OVER THE E. THERE ARE 2 SHRTWVS OF INTEREST EMBEDDED IN THE NW
FLOW...THE FIRST IS DIGGING SEWD INTO NW MN WHILE ANOTHER IS MOVING
SEWD THRU NRN MANITOBA/FAR NW ONTARIO. A FAIRLY VIGOROUS 998MB LO
OVER CENTRAL MANITOBA IS THE SFC REFLECTION OF THESE DISTURBANCES.
UPR MI IS UNDER THE SSW FLOW BTWN THIS LO AND SLOWLY RETREATING
ARCTIC HI PRES NEAR THE ONTARIO/QUEBEC BORDER. THE PRES GRADIENT IS
MUCH TIGHTER OVER MN CLOSER TO THE LO...AND SOME LIGHT SN IS NOTED
ON THE SFC OBS/RADAR COMPOSITES MOVING THRU NRN MN. ALTHOUGH NEARBY
RAOBS SHOW SOME MID LVL MSTR WITH 00Z H7 DEWPT DEPRESSIONS OF ONLY
2C AND 4C AT YPL AND INL RESPECTIVELY...THE RAOBS ALSO INDICATE SOME
LLVL DRY AIR LINGERS ACROSS THE AREA...WITH 00Z H85 DEWPT
DEPRESSIONS OF 26C AT MPX...22C AT GRB AND EVEN 13C AT INL/10C AT
YPL CLOSER TO THE SFC LO. SO THE OBSVD SN INTENSITY AND COVERAGE IS
NOT THAT GREAT DESPITE SOME FAIRLY STRONG ISENTROPIC ASCENT NOTED ON
THE 290K SFC /ABOUT H7/.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/SN AMOUNTS
ASSOCIATED WITH THE 2 SHRTWVS NOTED ABOVE. SINCE THERE ARE 2
DISTURBANCES/SEPARATE AREAS OF DEEP LYR FORCING...THE INITIAL SHRTWV
IS TENDING TO TRACK FARTHER W DUE TO THE HI AMPLITUDE PATTERN AND
LARGER SCALE MSTR INFLOW WL REMAIN FAIRLY LIMITED...EXPECT SN
AMOUNTS TO BE SUB ADVY.

SHRTWV NOW MOVING INTO NW MN IS PROGGED TO DIG SSEWD THIS MRNG...
WITH AREA OF DEEP LYR QVECTOR CNVGC/SHARPER ISENTROPIC ASCENT ON THE
290K SFC IMPACTING MAINLY JUST THE WRN CWA THIS MRNG. THE SECOND
SHRTWV WL REACH FAR NW LK SUP LATE THIS AFTN...WITH AREA OF
DPVA/DEEP LYR QVECTOR CNVGC BUT WEAKER ISENTROPIC ASCENT INFLUENCING
MUCH OF THE CWA THIS AFTN/EVNG BEFORE FADING OVERNGT WITH APRCH OF
TRAILING SHRTWV RDG AXIS AND DNVA/DEEP LYR QVECTOR DVGC. WHILE THE
EXPECTED FORCING MAY JUSTIFY LIKELY TO CATEGORICAL POPS UNDER THE
BETTER FORCING...LIMITED MSTR INFLOW WL BE A MAJOR LIMITING FACTOR.
IN FACT THE H7 SPECIFIC HUMIDITY FCST UP TO 2 G/KG OVER THE W THIS
MRNG INTO EARLY AFTN IS FCST TO DIMINISH DURING THE EVENT. SO
DESPITE A FAVORABLE DEPTH/LOCATION OF THE DGZ CENTERED ARND 10K
FT...EXPECT SN TOTALS NOT MORE THAN 1 TO PERHAPS 3 INCHES...
HEAVIEST OVER THE W HALF BECAUSE THESE AREAS WL BE IMPACTED BY BOTH
SHRTWVS. SINCE SLOWLY BACKING LLVL FLOW WL ATTEMPT TO MAINTAIN FEED
OF NEAR SFC DRY AIR INTO THE E...FCST LOWER POPS/SN AMOUNTS IN THAT
AREA. IN FACT...THE FAR E MAY SEE LITTLE SN THRU TNGT. ONE CONCERN
FOR HEAVIER SN WL BE OVER THE SCENTRAL LATER THIS AFTN/EVNG DOWWIND
OF LK MI IN THE LLVL SLY FLOW AND WHEN DEEPER MSTR/FORCING
ASSOCIATED WITH 2ND SHRTWV WL ARRIVE IN THE PRESENCE OF H85 TEMPS /-
10 TO -12C/ SUFFICIENTLY COLD FOR SOME LK ENHANCEMENT.
HOWEVER...FAIRLY SHARP DIRECTIONAL SHEAR WITH BACKING LLVL SE FLOW
TURNING TO THE SSW AT H85 AND MAINTAINING A FEED OF NEAR SFC DRY AIR
MAY OFFSET THIS POTENTIAL. BUT OPTED TO MAINTAIN SOME HIER
CATEGORICAL POPS/QPF CENTERED NEAR ESCANABA TO ACCOUNT FOR THE
POTENTIAL LK ENHANCEMENT.

TEMPS TODAY SHOULD RECOVER INTO THE 20S OVER MOST OF THE CWA EXCEPT
OVER THE E...CLOSER TO SLOWLY RETREATING HI PRES/CORE OF COLDER AIR
AND WHERE H85 TEMPS ARE FCST TO RISE NO HIER THAN -12 TO -13C.
LINGERING CLDS THRU TNGT WL GREATLY LIMIT THE DIURNAL TEMP FALL. THE
COLDEST TEMPS AOB 10F WL ONCE AGAIN OCCUR OVER THE E.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 105 AM EST MON JAN 26 2015

WITH THE 500MB LOW AND THE AXIS OF THE 500MB TROUGH SHIFTED OVER THE
NEW ENGLAND STATES TUESDAY...THE RIDGE CURRENTLY OVER THE W HALF OF
THE NATION WILL BE ABLE TO SHIFT ACROSS THE CENTRAL PLAINS AND UPPER
GREAT LAKES TUESDAY INTO EARLY WEDNESDAY.

AT THE SFC...A RIDGE WILL BE ABLE TO SLIDE ACROSS LAKE SUPERIOR
TUESDAY /EXTENDING FROM MN UP THROUGH NEWFOUNDLAND/...WHICH WILL
LINGER INTO TUESDAY NIGHT AS THE MAIN AREA OF HIGH PRESSURE PUSHES
INTO THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE RESULT WILL
BE A DRY PERIOD AT LEAST UNTIL MID DAY WEDNESDAY...ALTHOUGH THERE
MAY STILL BE SOME CLOUDS LINGERING/STUCK BELOW THE 850-900MB
SUBSIDENCE INVERSION. TRICKY CLOUD COVER FCST FOR THIS PERIOD.

WEDNESDAY LOOK TO BE THE LAST WARM DAY IN A WHILE...WITH
TEMPERATURES NEAR FREEZING. 850MB TEMPS ON S FLOW WILL RISE TO -1 TO
-4C THROUGH THE DAYTIME HOURS AS THICKER CLOUDS INVADE FROM THE NW.

AN ELONGATED AREA OF LOW PRESSURE OVER THE N AND CENTRAL PLAINS
WEDNESDAY MORNING WILL EDGE E ACROSS IL AND IN THURSDAY
MORNING...AND OFF TO THE LOWER GREAT LAKES AND OFF THE MID ATLANTIC
STATES FRIDAY. THIS WILL BRING A TROUGH ACROSS OUR AREA WEDNESDAY
NIGHT THROUGH THURSDAY EVENING...WHICH WILL BE ENHANCED BY THE
SUPPRESSION OF THE 500MB RIDGE WEDNESDAY EVENING AND THURSDAY. LOOK
FOR A WIDESPREAD 2-5IN OF SNOW WITH SLR VALUES AROUND 15:1. EXPECT
THE HIGHER VALUES OVER THE N HALF OF UPPER MI AS IT WILL LIKELY TAKE
UNTIL LATE AFTERNOON/EARLY EVENING FOR SNOW TO BEGIN S CENTRAL. WILL
NOT GO QUITE AS QUICK WITH THE INVADING PRECIP AS THE 00Z NAM...BUT
A BLENDED SOLUTION SOUNDS REASONABLE. A WINTER WX ADVISORY MAY BE
NEEDED IF THE 2-5IN CAN FALL IN A 12HR PERIOD. WILL CONTINUE TO LOOK
INTO THIS FOR POSSIBLE POSTING OF HEADLINES ON TUESDAY...AND
HIGHLIGHT THE POTENTIAL FOR LIGHT TO MODERATE SNOW IN THE HWO.

N FLOW BEHIND THE EXITING SFC TROUGH THURSDAY AFTERNOON WILL BE THE
START OF OUR COOL DOWN...WITH 850MB TEMPS FALLING TO -8 TO -10C.
WHILE NOT QUITE OPTIMAL FOR LAKE EFFECT YET...SOME LAKE ENHANCEMENT
WILL BE LIKELY ALONG THE UPSLOPE N SNOWBELTS ALONG LAKE SUPERIOR
THURSDAY AS THE SFC LOW EXITS TO THE LOWER GREAT LAKES/PENNSYLVANIA
FRIDAY EVENING.

DESPITE SFC-500MB RIDGING ON FRIDAY...A FEW LINGERING LES WILL
REMAIN ALONG THE LAKE SUPERIOR SHORELINES. DON/T EXPECT MUCH IN THE
WAY OF ACCUMULATIONS AS THE MOISTURE IS AGAIN TRAPPED BELOW 850MB.
BUT WILL THE MOISTURE LAYER IN THE DGZ /850MB TEMPS OF -15 TO
-17C/...SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE.

SLIGHTLY WARMER AIR WILL PUSH IN THROUGH EARLY SATURDAY MORNING AS
THE SFC RIDGE EXITS TO THE LOWER GREAT LAKES...AND IN ADVANCE OF LOW
PRESSURE DEVELOPING NEARING FROM THE N PLAINS STATES.

SOME OF THE COLDEST AIR OF THE SEASON WILL PUSH INTO THE UPPER GREAT
LAKES SATURDAY AFTERNOON ON. THERE CONTINUES TO BE SOME TIMING
ISSUES ON THE ORDER OF AROUND 6HRS...WHICH IS PRETTY MINOR THIS FAR
OUT IN THE FCST...AND A BLENDED SOLUTION LOOKS REASONABLE. 850MB
TEMPS OF -20 TO -30C WILL SETTLE IN SUNDAY AFTERNOON AS THE SFC LOW
EXITS AND THE MAIN 500MB TROUGH PUSHES ACROSS THE UPPER GREAT LAKES.
LOOK FOR FINE LES THAT WILL BE GOOD AT REDUCING VIS...ESPECIALLY IF
THE STRONGER NW WINDS OF THE 25/12Z ECMWF ARE CORRECT/.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1249 PM EST MON JAN 26 2015

IN THE WAKE OF STEADIER SNOW THAT AFFECTED KIWD THIS MORNING...
EXPECT MVFR CONDITIONS TO PREVAIL THIS AFTN. ANOTHER DISTURBANCE
TRACKING SSE WILL BRING A ROUND OF -SN TO KIWD/KCMX/KSAW LATE THIS
AFTN/EVENING. WHILE KIWD SHOULD REMAIN MVFR AS THE -SN
PASSES...STEADIER SNOW AT KCMX/KSAW WILL LIKELY DROP CONDITIONS
FROM VFR TO IFR. LINGERING MOISTURE BEHIND THE DISTURBANCE WILL
RESULT IN CONDITIONS FALLING TO IFR AT KIWD BY LATE EVENING. IFR/LOW
MVFR CIGS WILL LIKELY PERSIST AT ALL TERMINALS THRU TUE MORNING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 AM EST MON JAN 26 2015

EXPECT S WINDS UP TO 20-25 KTS OVER MUCH OF LAKE SUPERIOR INTO THIS
AFTERNOON AS THE PRES GRADIENT TIGHTENS BETWEEN HI PRES DEPARTING TO
THE E AND A LO PRES MOVING SOUTHEAST TOWARD WESTERN LAKE SUPERIOR.
WINDS WILL DIMINISH LATER THIS AFTERNOON AND TONIGHT AS THE LO
WEAKENS AND SLIDES TO THE S. THEN RELATIVELY LIGHT WINDS UNDER 20
KTS WILL PREVAIL THRU WED AS A HI PRES RIDGE AND RATHER SLACK PRES
GRADIENT DOMINATES THE AREA. LOOK FOR STRONGER N WINDS UP TO 25 KTS
TO RETURN ON THU AS A LO PRES MOVES E THROUGH THE LOWER GREAT LAKES
AHEAD OF HI PRES BUILDING THROUGH CENTRAL CANADA...TIGHTENING THE
PRES GRADIENT AGAIN OVER LAKE SUPERIOR. THE INFLUX OF COLDER AIR AND
WAVES BUILT UP BY THE GUSTY WINDS WILL LIKELY BRING A RETURN OF
FREEZING SPRAY TO AT LEAST PORTIONS OF THE LAKE. THE CLOSER APPROACH
OF THE HI ON FRI WILL BRING A RETURN OF MORE TRANQUIL CONDITIONS.
&&

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

$$

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


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