Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 122234
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
634 PM EDT SAT APR 12 2014

.UPDATE...
ISSUED AT 633 PM EDT SAT APR 12 2014

BASED ON LATEST RADAR IMAGERY SHOWING STEADILY DIMINISHING RETURNS
WITH ARRIVAL OF MID LVL DRYING...LOWERED GOING POPS QUICKER THAN
SHOWN BY PREVIOUS FCST. BEST CHC OF LINGERING PCPN WL BE OVER THE
FAR S CENTRAL CLOSER TO STNRY FNT IN THE LOWER LKS AND OVER THE NE
CWA CLOSER TO LINGERING AXIS OF HIER MID LVL RH SHOWN BY LATEST RUC
MODEL/COOLER CLD TOPS ON IR STLT IMAGERY. ALTHOUGH THIS DRYING ALF
OVER PCPN MOISTENED...SHALLOW COOL DOME NEAR THE SFC N OF THE STNRY
FNT WL FAVOR FOG DVLPMNT IN THE PRESENCE OF NOCTURNAL COOLING TNGT AS
SHOWN BY PREVIOUS FCST... MODIFIED THE FOG FCST A BIT TO BETTER BLEND
WITH NEIGHBORING OFFICES.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 357 PM EDT SAT APR 12 2014

UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH IN THE NORTHERN
ROCKIES. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING
THROUGH THIS AFTERNOON INTO THIS EVENING BEFORE THE DEEPER MOISTURE
AND Q-VECTOR CONVERGENCE DEPARTS TONIGHT AND THEN RETURNS AGAIN LATE
SUNDAY AFTERNOON. NAM ALSO SHOWS SOME ISENTROPIC LIFT AND MOISTURE
ON THE I290K-I305K SURFACES THROUGH 06Z TONIGHT...BEFORE THE LIFT
DEPARTS THE CWA.

LOW LEVEL MOISTURE LOOKS TO BE TRAPPED UNDER AN INVERSION
TONIGHT...SO WILL SEE SOME FOG DEVELOP ALONG WITH SOME DRIZZLE AND A
FEW SPRINKLES OVERNIGHT. PUT FOG INTO THE FORECAST WITH A MOIST EAST
NORTHEAST FLOW CONTINUING AND ALSO ADDED SOME DRIZZLE. DO NOT THINK
FREEZING DRIZZLE WILL OCCUR TONIGHT EXCEPT ON WINDSHIELDS AND
ELEVATED SURFACES AS GROUND TEMPERATURES LOOK TO BE WARM ENOUGH TO
KEEP ICE FROM FORMING...SO DID NOT PUT INTO THE FORECAST AND MOST
TEMPERATURES WILL BE ABOVE FREEZING OVERNIGHT. NEXT SYSTEM ARRIVES
LATE ON SUNDAY AND HAVE SOME CHANCE POPS LATE IN THE SOUTH. BEST
CHANCES FOR DRIZZLE TONIGHT AND SUNDAY MORNING WOULD BE IN UPSLOPE
AREAS. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 429 PM EDT SAT APR 12 2014

THE PERIOD START 00Z MON WITH A DEEP UPPER TROUGH STRETCHING FROM
WRN HUDSON BAY TO THE FOUR CORNERS REGION THAT IS SITTING BETWEEN AN
AMPLIFIED UPPER RIDGE OVER THE PACIFIC US/CANADIAN COAST AND A RIDGE
OFF THE ERN US SEABOARD. LOOKING AT MSLP AND LOW LEVEL WIND
FIELD...A STATIONARY FRONT/SFC TROUGH WILL EXTEND FROM OK TO NEAR
CHICAGO AND CENTRAL LOWER MI TO E OF LAKE HURON. MOISTURE FLOW FROM
THE GULF OF MEXICO INTO THE FRONT WILL BE EXCELLENT WITH
UNOBSTRUCTED SLY FLOW S OF THE FRONT. MODELS SHOW QUITE A BIT OF
CHANGE FROM THE REGION ON MON/MON NIGHT AS A SHORTWAVE EJECTS OUT OF
THE CENTRAL/SRN PLAINS WHILE THE UPPER TROUGH AXIS MOVES TO THE
CENTRAL CWA BY 12Z TUE /AS THE NRN PORTION OF THE UPPER TROUGH
DEEPENS BY 7 DAM AND CLOSES OFF INTO A LOW OVER SRN HUDSON BAY/. THE
PLAINS SHORTWAVE WILL STAY WELL SE OF THE CWA...BUT WILL HELP USHER
THE SFC FRONT FARTHER E OUT OF LOWER MI BY THE END OF MON. THE
COMBINATION OF HEIGHT FALLS /AROUND 10DAM BETWEEN 00Z AND 12Z MON/
AS THE UPPER TROUGH MOVES IN AND FORCING IN THE RIGHT ENTRANCE
REGION OF A 130+KT JET WILL FAVOR AREAS MAINLY SE OF THE CWA FOR THE
BEST PRECIP 00Z-18Z MON. HOWEVER...THE 12Z/12 NAM AND 12Z/12
GEM-REGIONAL HAVE THE FAVORED FORCING REGION FROM THE JET AND BETTER
MOISTURE FARTHER NW INTO THE SERN CWA. THE 12Z/12 GFS AND 00Z/12
ECMWF GENERALLY SHOW A QUARTER INCH OF QPF OR LESS OVER THE FAR SERN
CWA 00Z-12Z MON...WITH THE MOST PRECIP FROM MENOMINEE TO MANISTIQUE
AND NEWBERRY...WITH LITTLE OR NO PRECIP OVER NWRN UPPER MI. THE NAM
AND GEM-REGIONAL SHOW 0.60 INCHES OR LESS OF QPF...AGAIN...THE MOST
OVER THE EXTREME SERN CWA WITH LITTLE TO NO PRECIP FROM IRONWOOD TO
HOUGHTON. THESE DIFFERENCES ARE FAIRLY SIGNIFICANT...MAINLY FOR THE
FAR SERN CWA...AS MODELS CURRENTLY INDICATE MOST OF THE PRECIP
SHOULD FALL AS SNOW GIVEN MUCH COLDER AIR MOVING IN WITH THE UPPER
TROUGH. IF THE NAM/GEM VERIFY...THE FAR SERN CWA COULD SEE A FEW
INCHES OF SNOW SUN NIGHT ALTHOUGH SFC TEMPS WILL BE WARM ENOUGH TO
LIMIT AMOUNTS SOMEWHAT EARLY SUN NIGHT. THIS IS VERY TRICKY TO
FORECAST AS THERE SHOULD BE A SHARP CUT OFF OF PRECIP ON THE NW EDGE
OF THE SYSTEM...AND AM UNSURE WHERE THAT WILL BE. WILL USE A MIX OF
CONSENSUS GUIDANCE AND PERSISTENCE GIVEN THIS UNCERTAINTY. ASIDE
FROM THE EARLY DAY PRECIP POSSIBILITIES...SOME MINOR LAKE
EFFECT/UPSLOPE SNOW IS POSSIBLE IN THE NW FLOW MON AFTERNOON INTO
MON NIGHT GIVEN 850MB TEMPS OF -16C...BUT DRY AIR MOVING IN ON THE
BACK SIDE OF THE TROUGH SHOULD HELP TO LIMIT THIS PRECIP.

SOME ISOLATED TO SCATTERED SNOW SHOWERS CONTINUE ON ON TUE DUE TO NW
LOW LEVEL FLOW AND 850MB TEMPS OF -18C...BUT SINCE THE UPPER TROUGH
WILL BE MOVING E OF THE CWA AND A SFC RIDGE MOVING IN FROM THE
NW...AMOUNT SHOULD BE LIMITED. AFTER A VERY COLD MON NIGHT FOR THIS
TIME OF YEAR /LOWS FROM AROUND 10F INTERIOR W TO THE TEENS ALONG THE
GREAT LAKES/...TUE WILL ALSO BE RELATIVELY COOL WITH HIGHS IN THE
MID 20S N TO MID 30S FAR S /ABOUT 20 DEGREES BELOW NORMAL/.

MODEL AGREEMENT /AND THEREFOR FORECAST CONFIDENCE/ DECREASES ON
WEDNESDAY...AND EVEN MORE SUBSTANTIALLY THURSDAY INTO NEXT WEEKEND.
GENERALLY...MODELS SHOW AN UPPER TROUGH MOVING INTO THE CWA OVER THE
LAST HALF OF THE WORK WEEK. THE GFS RESULTS IN THE MOST DRAMATIC
WEATHER AS IT STALLS A FRONT OVER THE CWA WED INTO THU...WHICH WOULD
DROP SIGNIFICANT QPF /MOSTLY AS SNOW/ ACROSS PART OF THE CWA.
THAT...HOWEVER...IS THE MOST EXTREME MODEL PRECIP WISE WITH A LOW
CHANCE OF OCCURRENCE /BUT STILL POSSIBLE/. WITH THE POOR MODEL
AGREEMENT AND LOW CONFIDENCE...KEPT CONSENSUS CHANCE POPS IN THE
FORECAST. CONTINUED TO USE A CONSENSUS APPROACH THROUGH THE REST OF
THE FORECAST PERIOD WITH DECREASING CONFIDENCE WITH TIME.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 114 PM EDT SAT APR 12 2014

CONDITIONS WILL CONTINUE TO SLOWLY DETERIORATE THIS AFTERNOON WITH
FOG AND LOW CLOUDS MOVING IN AND SHOULD GO TO IFR/LIFR AT ALL SITES.
THIS WILL LAST THROUGH THE REST OF THE FORECAST PERIOD AS LOW LEVEL
MOISTURE REMAINS TRAPPED AND THERE WILL ALSO BE SOME UPSLOPE
COMPONENT TO THE WIND AS WELL TO KEEP DRIZZLE AND FOG IN THE AREA.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT SAT APR 12 2014

LOOKS LIKE THE EASTERN TWO THIRDS OF LAKE SUPERIOR WILL SEE NORTH
GALES TO 35 KNOTS ON MONDAY BEHIND A LOW PRESSURE SYSTEM THAT MOVES
INTO LAKE HURON. OTHERWISE...WINDS WILL STAY BELOW 20 KNOTS THROUGH
THE PERIOD.
&&

.HYDROLOGY...
ISSUED AT 429 PM EDT SAT APR 12 2014

SOME MINOR ICE JAMS CONTINUE TO BE NOTED ON HYDROGRAPHS...MAINLY ON
THE FORD RIVER BUT ALSO POSSIBLY ON THE ESCANABA RIVER NEAR CORNELL.
NO IMPACTS HAVE BEEN REPORTED FROM THE ICE JAMS.

EXPECT COLDER AIR TO SURGE IN SUNDAY NIGHT THROUGH THE FIRST HALF OF
THE WORK WEEK. THIS WILL SIGNIFICANTLY REDUCE OR EVEN END THE SNOW
MELT...AS HIGHS WILL ONLY BE IN THE 30S AND LOWS WILL BE WELL BELOW
FREEZING. SINCE 4-9 INCHES OF SNOW WATER EQUIVALENT STILL REMAINS
OVER PARTS OF WESTERN AND CENTRAL UPPER MICHIGAN...THERE IS STILL
PLENTY OF WATER AVAILABLE FOR THE SECOND PERIOD OF SNOW MELT OVER
THE NEXT COUPLE OF WEEKS.
&&

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

$$

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




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