Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 062119
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
419 PM EST FRI MAR 6 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 342 PM EST FRI MAR 6 2015

WNW FLOW ALOFT BROUGHT A REALLY WEAK WAVE ALOFT OVER UPR MICHIGAN
TODAY. MAINLY A SMATTERING OF MID CLOUDS AND JUST NOW SOME FLURRIES
ARE STARTING TO FORM OVER EASTERN CWA. INCREASING LOW-LEVEL MOISTURE
AND LIFT BLO H85 PER RAP ALONG SFC TROUGH CROSSING THE EASTERN CWA
MAY INCREASE LGT SNOW BRIEFLY INTO EARLY EVENING TO EAST OF P53 AND
NORTH OF ERY. RADAR ECHOES PRETTY LIGHT THOUGH...SO FLURRIES ARE
PROBABLY ALL THAT MOST AREAS WILL SEE. ONLY OTHER ISSUE TODAY HAS
BEEN GUSTY SW WINDS OVER EAST HALF. ERY EVEN GUSTED OVER 40 MPH
BRIEFLY EARLY THIS AFTN WITH HAZE REPORTED ON THE AWOS WHICH IS LIKELY
BLSN. WEBCAMS OVER REST OF THE EAST INDICATE THAT IS FAIRLY LOCALIZED
THOUGH. WINDS HAVE DIMINISHED OVER THE WEST HALF AS LOW-LEVEL JET
HAS MOVED EAST OF THE AREA. AFTER THE LIGHT SNOW/FLURRIES IN THE EAST
EARLY...A QUIET EVENING EXPECTED AS THERE ARE NOT A LOT OF CLOUDS
IMMEDIATELY UPSTREAM IN WAKE OF THE WEAK TROUGH MOVING ACROSS THIS
AFTN. TEMPS SHOULD FALL OFF INTO THE TEENS. PERHAPS IF WINDS BECOME
CALM FOR A WHILE COULD SEE SINGLE DIGITS FOR THE COLDEST SPOTS IN THE
INTERIOR.

CHANGES OCCUR OVERNIGHT THROUGH AS SHORTWAVE DIGGING SOUTHEAST OVER
NORTHERN SASKATCHEWAN AND MANITOBA BRING DEEPENING SFC LOW TO
NORTHERN PART OF LK SUPERIOR BTWN 09Z-12Z SATURDAY. MID-HIGH CLOUDS
SHOULD INCREASE BY MIDNIGHT OVER THE WEST AND SPREAD OVER REST OF
THE AREA OVERNIGHT. PRECIP CURRENTLY OVER SOUTHERN PORTION OF
SASKATCHEWAN WILL EXPAND AS THE SHORTWAVE AND LOW GET CLOSER TO THE
AREA. SFC OBS ACTUALLY SHOW LGT LIQUID PRECIP OCCURRING OVER
SASKATCHEWAN THIS AFTN...BUT IT APPEARS THAT THE WARMER AIR ABOVE 0C
AT H85 GETS SHUNTED TO THE SOUTH BEFORE MAKING IT INTO UPR MICHIGAN.
ONLY EXPECTING SNOW LATE TONIGHT INTO SATURDAY MORNING. SOUNDINGS
SHOW MOST OF THE MOISTURE ADVECTION AND STRONGEST LIFT OCCURS H8-H7
WITH TEMPS WELL WITHIN THE DGZ. SLR/S SHOULD BE AT LEAST 15:1 IF NOT
MORE TOWARD 20:1 WHERE LIFT IS MAXIMIZED ON TEMPS -15C TO -18C.
MIXING RATIOS AHEAD OF THE LOW UP TO 2G/KG WOULD SUPPORT 4 INCHES OF
SNOW OVER 12 HOURS...BUT DURATION OF THE SNOW IN THIS CASE WILL BE 3-
5 HOURS AT THE MOST. MAYBE COULD SEE A COUPLE INCHES OF SNOW BUT
OVERALL SNOW AMOUNTS WILL BE AN INCH OR LESS...A LITTLE MORE IF THE
FLUFFIER SLR/S MATERIALIZE FOR THE DURATION OF THE SNOW.

IN WAKE OF THE SNOW...WHICH ENDS FM WEST TO EAST ON SATURDAY...IT IS
POSSIBLE THERE COULD BE SOME BRIEF FREEZING DRIZZLE BEFORE TEMPS AT
H9-H85 COOL SUFFICIENTLY FOR STRICTLY SNOW AS THE MID-LEVEL MOISTURE
WILL BE OUT OF THE PICTURE BY THAT TIME. BEST CHANCE FOR ANY PRECIP
AT ALL BTWN 15Z-21Z WOULD BE OVER HIGHER TERRAIN OF WESTERN UPR
MICHIGAN WITH NW WINDS THAT DEVELOP BEHIND THE SFC LOW. AT LEAST
LIGHT LAKE EFFECT COULD ALSO DEVELOP IN THE AFTN AS H85 THERMAL
TROUGH WITH H85 TEMPS DOWN TO -14C AND SUFFICIENT MOISTURE AFFECT
MAINLY WESTERN CWA. HIGH TEMPS SHOULD REACH UPR 20S TO LOWER 30S
MOST LOCATIONS BEFORE COOLER AIR WORKS IN LATE IN THE DAY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 419 PM EST FRI MAR 6 2015

A WARMER PATTERN WILL BE TAKING HOLD OVER THE NEXT 7 DAYS. THE VERY
PESISTENT TROF THAT HAS DOMINATED ERN NAMERICA WILL BE GIVING WAY AS
POSITIVE HEIGHT ANOMALIES OVER WRN NAMERICA/NE PACIFIC DIMINISH AND
EXPAND EASTWARD...CAUSING THE ERN TROF TO LIFT NE AND DIMINISH IN
AMPLITUDE. THESE CHANGES WILL CAUSE ARCTIC AIR TO RETEAT AND WILL
ALLOW PACIFIC AIR TO MAKE INCREASING INROADS ACROSS THE CONUS. FOR
UPPER MI...THIS MEANS ABOVE NORMAL TEMPS WILL BE RETURNING TO THE
AREA...AND TEMPS WILL LIKELY BE ABOVE NORMAL ON THE MAJORITY OF DAYS
OVER THE NEXT 1 TO 2 WEEKS. A SERIES OF DISTURBANCES WILL TRACK
ALONG THE SRN EDGE OF THE RETREATING ARCTIC AIR...BUT WITH THE
DISTURBANCES PASSING N OF THE AREA NEXT WEEK...THE CHANGING PATTERN
WILL REMAIN A DRY ONE FOR UPPER MICHIGAN...CONTINUING THE DRY
SYNOPTIC THEME FOR THE YEAR SO FAR. IN FACT...EXCLUDING SUN...MANY
LOCATIONS MAY NOT SEE ANY MEASURABLE PCPN NEXT WEEK. FARTHER DOWN
THE LINE...THERE ARE STILL SOME HINTS THAT A MORE PERSISTENTLY BLO
NORMAL TEMP REGIME MAY RETURN LATE THIS MONTH...BUT PROBABLY NOT
SIGNIFICANTLY BLO NORMAL (MORE OF THE GEM ENSEMBLES OUT AT DAY 16
ARE SHOWING REBUILDING OF A FAR WRN NAMERICE RIDGE). PATTERN STILL
LOOKS TO REMAIN ON THE DRY SIDE.

BEGINNING SAT NIGHT/SUN...2 OR 3 SHORTWAVES WILL SWING THRU THE WRN
GREAT LAKES REGION. INITIALLY SAT NIGHT...850MB TEMPS OF -13 TO -14C
MAY SUPPORT SOME LIGHT NW FLOW LES. AS WINDS BACK WITH PASSAGE OF
SFC HIGH PRES RIDGE AND APPROACH OF LOW PRES TROF...THE LIGHT LES
WILL PUSH OFFSHORE OVERNIGHT. LATE IN THE NIGHT...FOCUS OF
WAA/ISENTROPIC ASCENT WILL DEVELOP WELL OFF TO THE SW IN SRN MN/NRN
IA...AND THAT`S WHERE THE MAIN AREA OF -SN WILL DEVELOP. HOWEVER...
DEEP LAYER FORCING AHEAD OF APPROACHING SHORTWAVE FARTHER N MAY
SPREAD SOME -SHSN/FLURRIES TO WRN LAKE SUPERIOR LATE. WITH THE
SHORTWAVE ARRIVING SUN AFTN...THERE MAY BE MORE OF A DIURNAL
COMPONENT TO -SHSN...MORE TYPICAL OF THIS TIME OF YEAR UNDER
INCREASING SOLAR INSOLATION. AFTER ANY LINGERING -SHSN/FLURRIES END
SUN EVENING WITH LOSS OF DAYTIME HEATING/DEPARTURE OF SHORTWAVE...
850MB TEMPS OF -11/-12C SHOULDN`T BE SUFFICIENT TO GENERATE ANY
LIGHT LES SUN EVENING.

RETREATING FLOW TO THE N WILL THEN LEAD TO WARMING FOR MON/TUE.
PERSISTENT WAA WILL CAUSE 850MB TEMPS OF -6 TO -11C MON MORNING TO
RISE TO 1 TO 4C BY TUE MORNING. DESPITE THE PERSISTENT
WAA/ISENTROPIC ASCENT...THE LOW TO MID LEVELS REMAIN DRY ACROSS THE
FCST AREA WITH BETTER MOISTENING INDICATED TO THE N AND E OF HERE...
CLOSER TO TRACK OF SHORTWAVE MOVING ACROSS NRN ONTARIO. SO...ONLY
EXPECT SOME MID AND HIGH CLOUDS. CLOUD COVER WILL OBVIOUSLY PLAY A
BIG ROLE IN SFC TEMPS...BUT IT APPEARS CLOUDS WON`T DOMINATE EITHER
DAY. SINCE SUNSHINE ON THE LOWER ALBEDO FORESTED TERRAIN OF UPPER MI
AT THIS TIME OF YEAR CAN SIGNIFICANTLY DIMINISH THE INFLUENCE OF
SNOW COVER ON DAYTIME HEATING...WILL CONTINUE TO LEAN TOWARD THE
WARMER SIDE OF AVBL GUIDANCE FOR MON-TUE. MOST LOCATIONS WILL SEE
HIGH TEMPS INTO THE 40S AT SOME POINT MON/TUE. CERTAINLY NOT OUT OF
THE QUESTION THAT SOME LOCATIONS WILL TOP 50F EITHER DAY...BUT MORE
LIKELY OVER THE SCNTRL ON TUE.

BIGGEST MODEL TREND SINCE YESTERDAY IS FOR SHORTWAVE TRACKING ACROSS
NRN ONTARIO TO BE QUICKER...AND THUS ASSOCIATED COLD FRONT DROPS
THRU UPPER MI SOONER THAN INDICATED BY MODELS YESTERDAY. WILL BE A
TREND TO MONITOR THAT MAY AFFECT TUE TEMPS. FOR NOW...THIS MEANS A
COOLER WED IS NOW EXPECTED AS SFC HIGH PRES RIDGING NOSES SE INTO
THE UPPER LAKES WED...RESULTING IN THE ADDITIVE CHILL OF LIGHT LOW-
LEVEL FLOW ACROSS LAKE SUPERIOR INTO UPPER MI. TIGHT 850MB TEMP
GRADIENT ACROSS UPPER MI/LAKE SUPERIOR (10C DIFFERENCE FROM SW UPPER
MI TO NE LAKE SUPERIOR) WILL SUPPORT A DECENT SFC TEMP GRADIENT
ACROSS THE FCST AREA. SCNTRL SHOULD STILL REACH THE LOW/MID 40S WED
WHILE LWR 30S SHOULD BE THE RULE ACROSS THE N AND E. ANOTHER
DISTURBANCE TRACKING ACROSS NRN ONTARIO MAY GENERATE PATCHY
-SN/FLURRIES WITHIN THE TIGHT TEMP GRADIENT...BUT AT THIS POINT...
POTENTIAL IS TOO LOW TO INCLUDE MENTION IN FCST.

ALTHOUGH WAA GETS UNDERWAY AGAIN THU...IT APPEARS BETTER POTENTIAL
OF COLUMN MOISTENING IN THE WAA/ISENTROPIC ASCENT WILL OCCUR DEEPER
INTO THE RETREATING COLD AIR TO THE N OF UPPER MI. WILL MAINTAIN A
DRY FCST FOR THU.

12Z GFS CONTINUES ALONG THE LINES OF SOME PREVIOUS RUNS IN BRINGING
WHAT WOULD LIKELY END UP AS A MIXED PCPN EVENT FRI IN ASSOCIATION
WITH PACIFIC ENERGY THAT MOVES ACROSS THE NRN PLAINS. UNTIL OTHER
GUIDANCE SUPPORTS THAT IDEA...WILL HOLD OFF FROM INCLUDING AN
EXPLICIT MENTION OF PCPN.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1253 PM EST FRI MAR 6 2015

SCT-BKN VFR CLOUDS THIS AFTN AND THROUGH MOST OF THE NIGHT. CLOUDS
LOWER TO MVFR OR LOWER VFR LATE TONIGHT INTO SATURDAY MORNING AS A
UPPER DISTURBANCE PRODUCES A 3-5 HOUR PERIOD OF LIGHT SNOW. VSBY MAY
DROP TO IFR AS THE SNOW MOVES THROUGH.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 342 PM EST FRI MAR 6 2015

NO GALES ARE EXPECTED THROUGH THE PERIOD. SOUTHWEST TO WEST WINDS TO
30 KTS AHEAD OF A SFC LOW PRESSURE SYSTEM AND TROUGH DIMINISH THIS
EVENING. EXPECT WEST TO NORTHWEST WINDS TO 30 KTS FOR SATURDAY
BEHIND THE DEPARTING LOW PRESSURE SYSTEM. WINDS DIMINISH LATER
SATURDAY THROUGH SUNDAY. ANOTHER ROUND OF SOUTHWEST TO WEST WINDS TO
30 KTS EXPECTED MONDAY AND TUESDAY AHEAD OF A COLD FRONT THAT DROPS
NORTH TO SOUTH ACROSS LAKE SUPERIOR BY WEDNESDAY MORNING. BEHIND
THAT FRONT...NORTHWEST WINDS SHOULD BE 25 KTS OR LESS ON WEDNESDAY.

LAKE SUPERIOR REMAINS MOSTLY ICE COVERED. ALREADY SEEING THE ICE
SHIFT AROUND THOUGH WITH THE STRONGER WINDS THAT OCCURRED SINCE
EARLY FRIDAY MORNING. EXPECT THE ICE COVERAGE TO DIMINISH SOME INTO
EARLY NEXT WEEK DUE TO THE STRONG AND SHIFTING WINDS AT TIMES AND
WITH DAYTIME TEMPERATURES RISING ABOVE FREEZING AT LEAST EARLY NEXT
WEEK.
&&

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

$$

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


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