748
FXUS63 KMQT 192010
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
310 PM EST WED FEB 19 2020
SHORT TERM
(THIS EVENING THROUGH THURSDAY)
ISSUED AT 252 PM EST WED FEB 19 2020
UPPER MICHIGAN REMAINS UNDERNEATH BROAD TROUGHING THIS AFTERNOON
WITH PREDOMINANTLY NW FLOW IN THE LOW TO MID LEVELS BACKING TO W
ALOFT AS CAA CONTINUES. IN THE ABSENCE OF DEEPER FORCING OR
MOISTURE, INVERSION HEIGHTS HAVE COME DOWN TO ABOUT 4-5 KFT PER NAM,
NAM HI-RES, GFS SOUNDINGS. MODEL SOUNDINGS SHOW MOISTURE DEEPENING
AGAIN BRIEFLY THIS EVENING ABOUT 00Z-06Z AS ANOTHER SHORT WAVE,
THOUGH MUCH WEAKER THAN LAST NIGHT'S, DROPS SOUTHEASTWARD ACROSS
LAKE SUPERIOR. STILL, THIS ADDITIONAL MOISTURE AND LIFT SHOULD GIVE
A BOOST TO THE LES BANDS THIS EVENING. WENT WITH THE HI-RES MODELS
FOR POPS AND LEANING TOWARDS THE CONSSHORT FOR QPF, AND ASSUMED SLRS
REMAINING AROUND 20:1 (WHICH WORKED WELL YESTERDAY BASED ON THIS
MORNING'S COOP REPORTS). THE RESULT IS ANOTHER 2-4" IN THE AREA EAST
OF SHINGLETON AND MELSTRAND OVER TO GRAND MARAIS AND CRISP POINT,
AND NORTH OF NEWBERRY, WITH UP TO 2" POSSIBLE IN THE PARTS OF THE
ADVISORY AREA THAT ARE OUTSIDE OF THAT AREA. THEREFORE, WILL EXTEND
THE WINTER WEATHER ADVISORY FOR THE EASTERN HALF OF THE NW WIND SNOW
BELTS UNTIL 09Z. SOME LIGHT LES WILL CONTINUE AFTER 09Z UNTIL ABOUT
15Z OR SO BUT AS INVERSION HEIGHTS DROP AND THE LOW LEVELS BEGIN TO
DRY OUT MORE THE SNOW WILL BECOME LIGHT ENOUGH THAT IT WON'T NEED
THE HEADLINE AT THAT POINT.
THE OTHER AREA TO WATCH WILL BE THE KEWEENAW AND WESTERN HALF OF THE
W WIND SNOW BELTS. THERE MAY BE A STRONGER CONVERGENCE BAND SETTING
UP IN THIS AREA AS THE W OR SLIGHT S OF W FLOW INTERIOR MEETS THE
WNW FLOW OVER THE KEWEENAW. WENT ABOUT 0.01-0.03" HIGHER IN QPF THAN
ANY MODEL BLEND IN THAT AREA BUT THAT STILL ONLY GIVES 1-2" OF NEW
SNOW TONIGHT. CAN'T REALLY JUSTIFY GOING ANY HIGHER THAN THAT GIVEN
HOW FAR OUTSIDE OF THE GUIDANCE ENVELOPE IT WOULD BE BUT AT THE SAME
TIME IT WOULDN'T SHOCK ME IF SOMEONE FROM PAINESDALE TO ONTONAGON
ENDS UP WITH A FEW INCHES OF MORE SNOW OVERNIGHT.
THE OTHER STORY THIS SHORT-TERM PERIOD WILL BE THE COLD TONIGHT INTO
TOMORROW MORNING. AS HIGH PRESSURE SETTLES SOUTH INTO THE
MISSISSIPPI VALLEY AND SKIES CONTINUE TO CLEAR OUTSIDE OF THE LAKE-
EFFECT BELTS, SHOULD SEE TEMPS DROP OFF QUICKLY OVERNIGHT. THE BIAS-
CORRECTED GUIDANCE ALL HAS A STRONG SIGNAL FOR SUBZERO LOWS SO WENT
WITH THE 25TH PERCENTILE OF GUIDANCE, THEN ADJUSTED BACK UPWARDS
TOWARDS THE WARMER CONSRAW WHERE CLOUD COVER WILL PERSIST. LOWS
SHOULD FALL TO ABOUT -15 TO -20 IN THE VERY COLDEST SPOTS OF GOGEBIC
COUNTY NEAR THE WISCONSIN LINE, -5 TO -15 OVER THE REST OF THE
WESTERN HALF OF THE INTERIOR, AND AROUND 0 OVER THE KEWEENAW, EAST,
AND ALONG THE LAKE SUPERIOR SHORELINE. WITH THE CENTER OF THE HIGH
WELL TO THE SOUTH, THERE WILL BE SOME PRESSURE GRADIENT REMAINING -
ENOUGH TO MAINTAIN ABOUT 3-5 KTS OF WIND THROUGH THE NIGHT. THIS
COULD BE ENOUGH TO GET WIND CHILLS DOWN INTO ADVISORY-CRITERIA OVER
GOGEBIC COUNTY TONIGHT BUT GIVEN HOW MARGINAL IT LOOKS AND HOW THE
COLDEST TEMPS AND STRONGER BREEZES RARELY OCCUR CONCURRENTLY, WILL
HOLD OFF ON ANY WIND CHILL ADVISORY. SUNNY SKIES TOMORROW SHOULD
HELP PUSH TEMPS BACK TOWARDS THE UPPER TEENS TO LOW 20S BY TOMORROW
AFTERNOON. WITH A BREEZY SW WIND DEVELOPING IN THE AFTERNOON IT MAY
STILL FEEL CHILLY DESPITE THE SUNSHINE.
LONG TERM
(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 129 PM EST WED FEB 19 2020
UPPER AIR PATTERN WILL CONSIST OF A 500 MB RIDGE ACROSS THE ROCKIES
WITH A TROUGH OFF THE WEST COAST AND ANOTHER IN THE ERN U.S. 00Z
FRI. THE RIDGE GETS FLATTENED A BIT 00Z SAT OVER THE ROCKIES AND
THEN MOVES OUT INTO THE PLAINS 00Z SUN AS A TROUGH MOVES INTO THE
WESTERN U.S. QUIET WEATHER WILL CONTINUE FOR THIS FORECAST PERIOD.
IN THE EXTENDED, THE GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
SOUTHERN ROCKIES WITH A SHORTWAVE OVER THE CANADIAN PRAIRIES 12Z
SUN. THE NORTHERN SHORTWAVE MOVES INTO THE UPPER GREAT LAKES REGION
12Z MON WITH THE SOUTHERN ONE MOVING INTO THE SOUTHERN MISSISSIPPI
RIVER VALLEY. MORE ENERGY MOVES INTO THE ROCKIES 12Z TUE WHICH DIGS
OUT AN AMPLIFIED TROUGH OVER THE ROCKIES. THIS AMPLIFIED TROUGH
MOVES INTO THE CENTRAL U.S. 12Z WED. ABOVE NORMAL TEMPERATURES WILL
COOL TO NEAR NORMAL FOR THIS FORECAST PERIOD. STORMY PATTERN WILL
CONTINUE WELL TO THE SOUTH OF THE AREA.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1231 PM EST WED FEB 19 2020
LAKE-EFFECT CLOUDS CONTINUE AT THE TERMINALS THIS AFTERNOON WITH
PERIODS OF MODERATE TO HEAVY LAKE-EFFECT SNOW AT CMX AS WELL.
HOWEVER IWD IS RIGHT ON THE EDGE OF THE CLOUD SHIELD AND SAW HAS
BEEN OSCILLATING BETWEEN VFR AND MVFR WITH INDICATIONS ON SATELLITE
THAT THE CIG IS STARTING TO BREAK UP. SO CONDITIONS WILL BE
IMPROVING TO VFR THROUGH THE AFTERNOON AT THOSE TWO SITES. CMX
SHOULD HOPEFULLY SEE A MINOR IMPROVEMENT TO IFR VIS LATE AFTERNOON
BEFORE LAKE-EFFECT SNOW BANDS RESTRENGTHEN THIS EVENING. MORE LIFR
VIS IS POSSIBLE WHEN THIS HAPPENS BUT SINCE THEY COULD WOBBLE BACK
AND FORTH HAVE JUST GONE WITH LOWER-END IFR AND TEMPO LIFR FOR THAT
PERIOD. CONDITIONS BEGIN TO IMPROVE AT CMX AFTER MIDNIGHT BUT EXPECT
THE MVFR CIG WILL HOLD ON THROUGH THE END OF THE TAF PERIOD.
MARINE
(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 310 PM EST WED FEB 19 2020
STIFF NW WINDS 25-30 KTS CONTINUE TONIGHT BEFORE BACKING TO W
THURSDAY MORNING. WSW GALES TO 40 KTS DEVELOP ON THE WESTERN HALF OF
THE LAKE THURSDAY AFTERNOON THROUGH FRIDAY MORNING. WINDS RELAX TO
20 KTS BY SATURDAY MORNING WITH NO OTHER PERIOD OF STRONG WINDS
ANTICIPATED THROUGH AT LEAST THE BEGINNING OF NEXT WEEK. HEAVY
FREEZING SPRAY WILL REMAIN A CONCERN THROUGH THURSDAY AFTERNOON AS
WELL.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY
FOR LSZ162-240>251-263>267.
GALE WARNING FROM 1 PM EST /NOON CST/ THURSDAY TO 4 AM EST /3 AM
CST/ FRIDAY FOR LSZ162-240>244-249-250-263-264-266.
LAKE MICHIGAN...
NONE.
SHORT TERM...RJC
LONG TERM...07
AVIATION...RJC
MARINE...RJC
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