Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KMQT 290821
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
321 AM EST SAT NOV 29 2014

.UPDATE...
ISSUED AT 913 PM EST FRI NOV 28 2014

LATEST GRB RADAR IMAGERY INDICATES BAND OF LES JUST E OF THE DOOR
PENINSULA IS RATHER WEAK. EVEN THOUGH LLVL SSE FLOW NOTED ON OBS
PLATFORMS OVER NRN LK MI WL TEND TO LIFT THIS BAND INTO DELTA COUNTY
LATER IN THE EVNG...LOWERED QPF/FCST SN AMOUNTS A BIT BASED ON THE
RATHER WEAK LOOK TO THE BAND...AN ABSENCE OF ANY COLDER CLD TOPS IN
THE AREA WITH MINIMAL UPR FORCING THAT WL LIMIT ENHANCEMENT...LO
INVRN BASE NEAR H9 AS SHOWN ON THE 00Z GRB RAOB IN THE ABSENCE OF
THAT FORCING AND EXPECTED SHIFTING WINDS WITH TIME/HGT THAT SHOULD
LIMIT RESIDENCE TIME/BAND INTENSITY. ARRIVAL OF HIER H85 TEMPS LATER
AT NGT WL TEND TO WEAKEN THE BANDS FURTHER AS THEY SHIFT TOWARD
MANISTIQUE.
&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 248 PM EST FRI NOV 28 2014

COMPLEX SHORT TERM...AS IS NORMALLY THE CASE DURING TRANSITIONS FROM
SNOW TO MIXED PRECIP AND FREEZING RAIN/DRIZZLE.

A FAST MOVING AREA OF SNOW HAS BEEN TRACKING ACROSS THE SRN CWA
TODAY AND IS NOW MOVING INTO THE SERN CWA. THE SNOW IS AHEAD OF A
WEAK SHORTWAVE CURRENTLY OVER MN AND IN AN AREA OF WAA. GENERALLY UP
TO 1 INCH OF SNOW HAS BEEN OBSERVED WITH THE SYSTEM SNOW. ADDITIONAL
MORE ISOLATED SNOW SHOWERS ARE LOCATED W/WSW OF THE CWA MORE TOWARD
THE SHORTWAVE...WHICH WILL MAINLY MOVE ALONG AND S OF THE WI BORDER
THROUGH THIS AFTERNOON.

LATER THIS EVENING INTO THE OVERNIGHT HOURS ATTENTION TURNS TO AREAS
NEAR LAKE MICHIGAN AS SLY WINDS BRING AN LES BAND NOW ARCHING TO THE
MACKINAC BRIDGE INTO THE AREA. ADDITIONALLY...UPSLOPE/ONSHORE S-SSE
FLOW WILL BRING SNOW SHOWERS TO MUCH OF THE AREA MAINLY E OF A LINE
FROM SAWYER TO MENOMINEE. DO NOT THIS THIS BAND WILL DROP AS MUCH
SNOW IN ANY ONE AREA AS PREVIOUSLY THOUGHT DUE TO MODELS SHOWING THE
BAND BEING MORE TRANSIENT. THIS MAKES SENSE GIVEN THAT LOW LEVEL
FLOW WILL VEER WITH HEIGHT AND ALSO WINDS WILL VEER WITH TIME. HAVE
AROUND 2 INCHES OF SNOW FOR THESE AREAS FROM NOW THROUGH TONIGHT.

THINGS BECOME MORE COMPLICATED LATE TONIGHT AS AN 800-900MB WARM
NOSE WITH ABOVE FREEZING TEMPS MOVES IN FROM THE SW. PRECIP AT THIS
POINT WILL BE MAINLY CONFINED TO DOWNSTREAM OF LAKE MICHIGAN...BUT
LIGHT/ISOLATED PRECIP IS ALSO POSSIBLE ELSEWHERE AS WAA CONTINUES.
ADDITIONALLY...MODELS SHOW A NARROW AREA OF PRECIP AT OR S OF
MENOMINEE ASSOCIATED WITH ANOTHER WEAK SHORTWAVE CURRENTLY OVER ND
RIGHT AROUND THE TIME OF PTYPE TRANSITION. NATURALLY LOTS OF
UNCERTAINTY HOW MUCH AND WHERE THIS PRECIP WILL OCCUR. PRECIP MAY
INITIALLY BE SLEET DURING THE TRANSITION TO FREEZING RAIN AND
EVENTUALLY FREEZING DRIZZLE AS THE DGZ DRIES OUT. IF THAT BAND DOES
SET UP OVER MENOMINEE...GREATER AMOUNTS OF INITIALLY SNOW...THEN
POSSIBLY SLEET AND FREEZING RAIN WOULD OCCUR. MAIN AREA OF CONCERN
WITH FREEZING PRECIP IS DOWNSTREAM OF LAKE MICHIGAN...MAINLY NEAR
AND E OF A LINE FROM MANISTIQUE TO NEWBERRY...WHERE FLOW OFF LAKE
MICHIGAN WILL KEEP PRECIP GOING AS LAKE EFFECT PRECIP COMES TO AN
END. TRANSITION WILL OCCUR CLOSER TO 12Z OVER THE ERN U.P. EVEN WITH
HIGH TEMPS EXPECTED TO BE IN THE MID 30S SAT...ROAD SFC TEMPS IN THE
LOW TO MID 20S WILL LEAD TO ANY LIQUID PRECIPITATION FREEZING ON
CONTACT WITH UNTREATED ROADWAYS...ESPECIALLY BARE ROADS AND ROADS
COVERED IN HARD PACKED SNOW. THEREFORE...MAIN THREAT FROM FREEZING
PRECIP IS ON ROAD/SIDEWALKS...WITH NO SIGNIFICANT THREAT TO ELEVATED
SURFACES. AM NOT VERY CONFIDENT ON AMOUNT OF FREEZING PRECIP
ACCUMULATIONS. WITH FRESH SNOW FALLING TONIGHT /HOPEFULLY HELPING TO
MAKE A CRUSTY COVER ON THE ROADS WHEN THE FREEZING PRECIP
FALLS...THUS KEEPING THE ROADS FROM BECOMING AS SLICK/...AND THE
POTENTIAL IMPACTS FROM FREEZING PRECIP BEING VERY DEPENDENT ON ROAD
SURFACE TREATMENT AND CLEARING OF THE SNOW OFF THE ROADS...WILL NOT
ISSUE ANY HEADLINES FOR THE FREEZING PRECIP. HOWEVER...WILL ISSUE AN
SPS HIGHLIGHTING THE THREAT OVER THE ERN AREAS. ANOTHER AREA THAT
MAY SEE BETTER CHANCES OF FREEZING PRECIP IS THE KEWEENAW PENINSULA
AS SSE WINDS UPSLOPE INTO NRN PORTIONS OF THE PENINSULA...BUT AM
LESS CERTAIN IN THIS AREA AND THINK AMOUNTS WILL BE LOWER THAN OVER
THE ERN UPPER PENINSULA. PRECIP SHOULD DIMINISH SOME OVER THE ERN
U.P. AND THE NRN KEWEENAW SAT AFTERNOON...BUT NOT COMPLETELY END.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT NOV 29 2014

NAM SHOWS A 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z SUN WHICH
MOVES INTO THE UPPER GREAT LAKES LATE SUN INTO MON AND THEN RAPIDLY
MOVES OUT OF THE AREA MON NIGHT. NAM AND GFS SHOW 850-500 MB
Q-VECTOR CONVERGENCE MOVING THROUGH 12Z SUN.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT TO SLOW
COLD AIR DOWN A BIT FOR SUNDAY WHICH LEADS TO MIXED PCPN ISSUES IN
THE MORNING AS THE COLD AIR MOVES QUICKLY ACROSS THE CWA. BY
AFTERNOON...ALL THE PCPN SHOULD BE SNOW ACROSS THE AREA.
TEMPERATURES WILL ALSO BE FALLING THROUGHOUT THE DAY ON SUNDAY AND
MOST OF THIS PERIOD WENT WITH A NON-DIURNAL TEMPERATURE CURVE
ESPECIALLY SUNDAY AND MONDAY NIGHT WITH LOW TEMPERATURES EARLY IN
THE EVENING...THEN TEMPERATURES RISING AFTER MIDNIGHT AS THE COLD
AIR RETREATS. LAKE EFFECT SNOW DOES NOT LOOK TO GET TOO OUT OF HAND
AS THE AIRMASS IS REALLY DRY COMING ACROSS THE AREA AND 850 MB
TEMPERATURES ARE REALLY COLD DOWN TO -26C SUNDAY NIGHT INTO MONDAY
MORNING.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH IN THE NORTHERN
ROCKIES AND A BROAD TROUGH ACROSS THE EASTERN U.S. 12Z TUE. THE
TROUGH IN THE NORTHERN ROCKIES MOVES INTO THE UPPER GREAT LAKES 12Z
WED AND THIS TROUGH STAYS AROUND INTO THU WITH THE UPPER LEVELS
BECOMING MORE ZONAL FOR FRI. WHAT THIS WILL MEAN IS A WARMING TREND
WITH TEMPERATURES REMAINING BELOW NORMAL THIS FORECAST PERIOD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1240 AM EST SAT NOV 29 2014

AS MORE LLVL MSTR IS ADVECTED INTO THE AREA EARLY THIS MRNG IN A
LLVL SE VEERING S WIND...EXPECT IFR TO LIFR CONDITIONS WITH AN
UPSLOPE WIND COMPONENT AT SAW AND POSSIBLY SOME -FZDZ BY 09Z
FOLLOWING SOME MID LVL DRYING. THE TRANSITION TO MORE AUSTERE
CONDITIONS WL BE SLOWER DESPITE SOME ISOLD SHSN THAT MIGHT IMPACT
CMX AND ESPECIALLY IWD...WHERE THE EXPECTED WIND DOWNSLOPES. BUT
EVEN AT THESE SITES...PREDOMINANT MVFR CONDITIONS ARE LIKELY BY
DAYBREAK DUE TO THE LLVL MSTR SURGE. THE -FZDZ COULD IMPACT CMX AS
WELL ON SAT...BUT RISING TEMPS ABOVE 32 IN THE CONTINUED SLY FLOW WL
BRING ABOUT A CHANGE TO JUST -DZ LATER ON AT SAW/CMX AS CIGS RISE
INTO THE MVFR RANGE AT SAW WITH A VEERING FLOW TOWARD A LESS FVRBL
SW AND THEN W DIRECTION IN THE EVNG. THIS WSHFT TO THE W WL BRING
IFR CONDITIONS TO IWD AND CMX THIS EVNG AS THE FLOW UPSLOPES. SOME
-FZDZ COULD DEVELOP AT IWD AND RETURN TO CMX WITH THE ARRIVAL OF
SHALLOW COLDER AIR.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 248 PM EST FRI NOV 28 2014

A DEVELOPING LOW PRESSURE SYSTEM OVER THE PLAINS WILL CONTINUE TO
MOVE TOWARD THE UPPER GREAT LAKES INTO SATURDAY. THIS WILL ALLOW FOR
WINDS TO GRADUALLY TURN SOUTH LATER TODAY INTO TONIGHT...BUT THEY
SHOULD STAY BELOW 20-25 KT. THE FRONT MOVES THOUGH SUNDAY...WHILE
STRONG ARCTIC HIGH PRESSURE BUILDS INTO THE PLAINS. THIS WILL ALLOW
NW GALES TO DEVELOP LATER SUNDAY AND CONTINUE INTO MONDAY. THE HIGH
RAPIDLY SHIFTS OVER THE LAKE MONDAY AFTERNOON...THEN MOVES INTO
QUEBEC BY TUESDAY. HIGH WILL ALLOW FOR A BRIEF RESPITE OF GALES MON
AFTN INTO MONDAY NIGHT...WITH SOUTHERLY GALES POSSIBLE AGAIN ON
TUESDAY ON THE BACK SIDE OF THE HIGH.
&&

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

$$

UPDATE...KC
SHORT TERM...TITUS
LONG TERM...07
AVIATION...KC
MARINE...TITUS






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.