Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 241759
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
159 PM EDT TUE MAR 24 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 557 AM EDT TUE MAR 24 2015

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MESSY COMPLEX OF
SHORTWAVE ENERGY MOVING ACROSS THE PACIFIC NW AND ROCKIES. LEAD
ENERGY IS ALREADY GENERATING SHRA/TSRA ACROSS THE CNTRL PLAINS EARLY
THIS MORNING. CLOSER TO HOME...SHORTWAVE RIDGE OVER MN IS SUPPORTING
SFC HIGH PRES OVER THE GREAT LAKES. ASSOCIATED DRY AIR
MASS/SUBSIDENCE AHEAD OF RIDGE IS RESULTING IN CLEAR SKIES ACROSS
THE UPPER LAKES EARLY THIS MORNING. WITH LIGHT/CALM WIND...TEMPS IN
THE INTERIOR E HALF HAVE FALLEN INTO THE LOWER TEENS AND SINGLE
DIGITS WITH A FEW SPOTS RECENTLY NEAR 0F. OUT W...20S ARE MORE
COMMON WITH A LIGHT S WIND STIRRING.

MID/UPPER RIDGE SHIFTING ACROSS THE WRN GREAT LAKES TODAY ALONG WITH
DRY AIR MASS WILL RESULT IN ABUNDANT SUNSHINE. HIGH WILL REACH THE
40S OVER THE MUCH OF THE W HALF. S TO SE WINDS OFF LAKE MI WILL KEEP
THE E HALF COOLER IN THE 30S...PROBABLY LOW 30S NEAR THE SHORE OF
LAKE MI.

TONIGHT...ATTENTION TURNS TO THE MULTIPLE SHORTWAVES CURRENTLY
MOVING ACROSS THE PACIFIC NW AND ROCKIES. LEAD ENERGY MOVING OUT
ACROSS NE/KS THIS AFTN IS STILL FCST TO TAKE ON A NEGATIVE TILT AS
IT MOVES TO VCNTY OF SRN LAKE MI BY 12Z WED WHILE ANOTHER SHORTWAVE
MOVES ACROSS THE DAKOTAS INTO MN. THIS WILL LEAD TO 2 SFC LOW
CENTERS AT 12Z WED...ONE OVER NW MN AND THE SECOND IN THE VCNTY OF
SRN LAKE MI. OVER THE LAST FEW DAYS...MODELS HAVE PERSISTENTLY
OVERALL TRENDED SLIGHTLY SE WITH EACH SUCCESSIVE MODEL RUN IN REGARD
TO THE SRN SHORTWAVE/SFC LOW. THAT TREND HAS CONTINUED WITH THE 00Z
MODELS. FOR THE FCST AREA...THIS MEANS HEAVIEST PCPN SHOULD PASS BY
TO THE SE OF HERE...AND PCPN SHOULD FALL ALMOST EXCLUSIVELY AS SNOW
AS IT ARRIVES FROM THE S AND SW LATE TONIGHT. THERE IS STILL JUST
ENOUGH UNCERTAINTY IN THERMAL PROFILES TO INCLUDE A MENTION OF -FZRA
CLOSE TO LAKE MI WHERE WARM NOSE ALOFT OF ABOVE FREEZING TEMPS WILL
COME CLOSE TO THAT AREA. UTILIZED MOSTLY A CONSENSUS APPROACH OF ALL
AVBL GUIDANCE...WEIGHTED TOWARD HIGH RES GUIDANCE (NAM/GEM AND NCEP
HRW-ARW/NMM)...TO CONSTRUCT POPS/QPF TONIGHT. RESULT IS PCPN
SPREADING N AND NE INTO THE FCST AREA AFTER 06Z. IT`S POSSIBLE THE
SNOW MAY NOT ARRIVE OVER THE FAR N AND E FCST AREA UNTIL AROUND 12Z
WED. RESULT FOR QPF IS ROUGHLY 0.10 TO 0.25 INCHES BY 12Z...HIGHEST
IN SRN MENOMINEE COUNTY. VIGOROUS DYNAMICS AND HEALTHY ISENTROPIC
ASCENT NOTED ON 290K SFC SHOULD LEAD TO DECENT PCPN RATES DURING
PEAK FORCING WHICH REACHES THE WI BORDER IN THE 09Z-12Z TIME FRAME.
ALTHOUGH MIXING RATIOS OF 3-4G/KG ARE AVBL AROUND 750MB...SHORT
DURATION OF STRONG FORCING AND LOWER SNOW TO WATER RATIOS DOWN TO 10-
15 TO 1 MAKE FOR LOWER CONFIDENCE ON SNOW ACCUMULATIONS REACHING
ADVY LEVEL. AT THIS POINT...CONSENSUS HERE IS TO HOLD OFF ON ADVY
HEADLINES...ESPECIALLY SINCE THIS IS A VERY LATE 2ND PERIOD AND 3RD
PERIOD EVENT. IF NEXT ROUND OF MODEL RUNS TODAY PAINT A SLIGHTLY
HIGHER QPF PICTURE...CAN FORESEE ADVY HEADLINES FOR POSSIBLY THE E
HALF OF THE FCST AREA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 517 AM EDT TUE MAR 24 2015

FCST MODELS CONTINUE TO MERGE ON A THEME OF HAVING THE INITIAL LOW
FROM THE SW OVER CENTRAL LAKE MI AROUND 12Z WEDNESDAY. THE RESULT
HAS BEEN A TREND TO LESS PRECIP AND MORE IN THE FORM OF SNOW INSTEAD
OF FREEZING RAIN WEDNESDAY MORNING.

PRECIP WILL OVERSPREAD THE REST OF THE CWA WEDNESDAY MORNING. THIS
QUICK BLAST OF MOISTURE WILL ALREADY BE PULLING OUT OF THE SW CORNER
OF UPPER MI BY 18Z WEDNESDAY...AND IF THE 23/18Z RUN OF THE CANADIAN
IS CORRECT MUCH OF THE SW AND CENTRAL CWA. THIS WILL BE WHILE THE
SFC LOW SHIFTS ACROSS E UPPER MI AND NW LAKE HURON BY 18Z...AND
GENERALLY BETWEEN CYLD AND CYXR IN SE ONTARIO BY 00Z THURSDAY. WITH
SFC TEMPS GETTING INTO THE UPPER 30S AND LOW 40S WEDNESDAY
AFTERNOON...SNOW WILL BE DIFFICULT TO MAINTAIN. WHILE A MIX IS
REPRESENTED IN THE FCST...UPPER MI WILL BE IN A LULL...WITH MUCH OF
THE BEST MOISTURE WILL BE ALREADY GONE.

UPDATED THE SPS TO INCLUDE THE COUNTIES OF MENOMINEE TO ALGER AND
E...WHERE THE GREATEST POTENTIAL FOR OVER 2IN OF SNOW EXISTS...ALONG
WITH A BRIEF PERIOD OF FREEZING RAIN.

WILL NEED TO WAIT UNTIL THE SECONDARY SFC LOW /OVER NW MN AT 12Z
WEDNESDAY/ EXITS THE PICTURE. IT SHOULD MOVE OVER NE MN AT 18Z
WEDNEDAY...AND JOIN FORCES WITH THE MAIN LOW EARLY WEDNESDAY EVENING
OVER LAKE SUPERIOR AND SE ONTARIO. 850MB TEMPS STILL AROUND -5C AT
00Z THURSDAY WILL FALL TO AROUND -15C OVER THE W BY 12Z THURSDAY ON
N-NW WINDS. THE RESULT...WITH THE ASSISTANCE OF THE SIZABLE 500MB
TROUGH OVERHEAD CONTINUING TO BRING A SERIES OF SHORTWAVES ACROSS
UPPER MI...WILL BE LIGHT TO AT TIMES MODERATE LES THROUGH THURSDAY
EVENING.

THE 500MB TROUGH WILL EVENTUALLY SHIFT TO OUR SE...MAKING WAY FOR A
RIDGE SATURDAY INTO EARLY SUNDAY. AT THIS POINT...WITH HIGH PRESSURE
AT THE SFC AND ALOFT...DRY WEATHER IS FIGURED FROM LATE MORNING
FRIDAY THROUGH THE DAY SATURDAY.

THE 00Z RUN OF THE ECMWF IS MORE ROBUST WITH THE PRECIP SUNDAY
MORNING. LOOKS LIKE ANOTHER POTENTIAL RAIN/SNOW SITUATION. WHILE THE
ECMWF WOULD INDICATE WARMER AIR AND A BETTER CHANCE OF RAIN...THE
GFS IS MUCH COOLER AND WOULD GIVE MAINLY RAIN. WILL CONTINUE WITH A
MODEL BLEND FOR THIS PERIOD...UNTIL A MORE SOLID CONSENSUS IS
DEVELOPED.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 151 PM EDT TUE MAR 24 2015

VERY DRY AIR IN THE LOW TO MID LEVELS ASSOCIATED WITH HIGH PRES
MOVING E ACROSS THE LOWER GREAT LAKES TODAY WILL ENSURE VFR
CONDITIONS AT KIWD/KCMX/KSAW THROUGH THIS EVENING. LOW PRES LIFTING
NE TOWARD LAKE MICHIGAN TONIGHT WILL SPREAD SNOW INTO UPPER MI LATE
TONIGHT INTO WED MORNING. IFR CONDITIONS SHOULD REACH KIWD BY 10Z AND
KCMX BY 14Z AND THEN IMPROVE BACK UP TO MVFR BY LATE WED
MORNING/EARLY AFTERNOON. KSAW HAS BEST POTENTIAL FOR HEAVIER SNOW
CLOSER TO TRACK OF SFC LOW SO EXPECT CONDITIONS THERE TO LOWER TO
LIFR SHORTLY AFT 12Z AND THEN IMPROVE BACK TO MVFR BY 16Z AS SYSTEM
LIFTS QUICKLY E.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 557 AM EDT TUE MAR 24 2015

WITH HIGH PRES OVER THE GREAT LAKES REGION SHIFTING E WHILE LOW PRES
DEVELOPING OVER THE SRN PLAINS MOVES NE...WINDS WILL INCREASE TODAY
AND TONIGHT. SINCE PRES GRADIENT REMAINS RELATIVELY WEAK...WINDS
ACROSS LAKE SUPERIOR SHOULD REMAIN MOSTLY UNDER 20KT...THOUGH HIGH
OBS PLATFORMS WILL PROBABLY SEE SOME GUSTS TO AROUND 25KT. WINDS
WILL DIMINISH WED AS LOW PRES TROF SETS UP ACROSS THE LAKE BTWN ONE
LOW PRES CENTER MOVING E TOWARD LAKE SUPERIOR AND THE OTHER LIFTING
NE THRU LWR MI INTO ONTARIO. THE TROF WILL DROP S OF THE LAKE WED
NIGHT...AND WINDS WILL THEN INCREASE INTO THU AS HIGH PRES BUILDS S
TOWARD THE NRN PLAINS AND MUCH COLDER AIR SPREADS SE INTO THE UPPER
LAKES. NORTHERLY WINDS SHOULD INCREASE TO 20-30KT THU...AND IT`S NOT
OUT OF THE QUESTION THAT GALE FORCE GUSTS COULD OCCUR FOR A TIME
OVER CNTRL PORTIONS OF LAKE SUPERIOR. WINDS WILL THEN DIMINISH FRI
AS THE HIGH PRES ARRIVES OVER THE WRN GREAT LAKES. WIND WILL BEGIN
TO RAMP UP AGAIN SAT...ESPECIALLY LATE...AS THE HIGH SHIFTS TO THE
OHIO VALLEY AND LOW PRES DROPS SE INTO MANITOBA.
&&

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

$$

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


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