656
FXUS63 KMQT 161732
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
132 PM EDT WED OCT 16 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 456 AM EDT WED OCT 16 2013
AS OF 08Z THIS MORNING...A SFC/850MB LOW IS OVER ERN UPPER MI/NRN
LAKE MICHIGAN...WITH THE UPPER TROUGH AXIS OVER WCENTRAL UPPER MI.
PRECIP HAS BEEN ONGOING IN THE DEFORMATION ZONE TO THE N/NW OF THE
85MB LOW...WITH ADDITIONAL PRECIP OVER NRN WI ASSOCIATED WITH A
TROWAL ON THE BACK SIDE OF THE SYSTEM. BY 18Z TODAY...THE UPPER
TROUGH AXIS WILL BE JUST E OF THE CWA WITH THE SFC LOW EVEN FARTHER
E. BEHIND THE SYSTEM...A SFC/UPPER RIDGE AXIS WILL BE JUST NW OF THE
CWA. EXPECT RAIN TO BE ONGOING ACROSS MAINLY THE NCENTRAL AND ERN
CWA BY 15Z...WITH MORE ISOLATED RAIN SHOWERS OVER WRN UPPER MI. THE
SHOWERS WILL BE DUE TO THE TROWAL OVER THE ERN CWA...WHILE THE REST
OF THE CWA WILL BE SEEING UPSLOPE/LAKE EFFECT PRECIP AS 850MB TEMPS
WILL BE AROUND 0C WITH NNW LOW LEVEL WINDS. WENT WITH HIGHER-RES
MODELS FOR POPS AS THEY SEEMED MORE REALISTIC WITH UPSLOPE/LAKE
EFFECT PRECIP...THOUGH DID NOT GO WITH AS HIGH/LONG OF POPS AS THE
REGIONAL GEM SUGGESTED SINCE IT WAS AN OUTLIER ON THE HIGH END OF
QPF.
WITH THE RIDGE MOVING OVERHEAD TONIGHT...CLEAR SKIES AND LIGHT WINDS
OVER INTERIOR W AND CENTRAL WILL MAKE FOR A COLD NIGHT. LOWERED MIN
TEMPS TONIGHT BY 3-4F TO 24-28F OVER THE INTERIOR AS MANY MODELS
WERE GOING WITH COLDER TEMPS AND IT SEEMED REASONABLE GIVEN CLEAR
SKIES/SUBSIDENCE AND PWATS AROUND 50 PERCENT OF NORMAL. OVER THE ERN
CWA...THINK THAT ENOUGH UPSLOPE/LAKE EFFECT CLOUDS WILL STICK AROUND
TO KEEP TEMPS FROM FALLING AS COLD...BUT STILL EXPECT LOWS AROUND
FREEZING INLAND. OVER FAR WRN UPPER MI...HIGH CLOUDS WILL START TO
FILTER IN LATER IN THE NIGHT AHEAD OF THE NEXT SYSTEM...SO LOW TEMPS
WILL BE A BIT WARMER THERE AT AROUND 30F INLAND FROM LAKE SUPERIOR.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 456 AM EDT WED OCT 16 2013
IN CONTRAST TO THE WARM WEATHER THAT GENERALLY DOMINATED MOST DAYS
DURING THE FIRST 2 WEEKS OF OCT...THE NEXT 1-2 WEEKS WILL FEATURE
DAILY TEMPS NEAR OR A LITTLE BLO NORMAL MOST DAYS. THIS IS A RESULT
OF A MEAN TROF SETTING UP IN THE VCNTY OF THE GREAT LAKES REGION
DOWNSTREAM OF A MEAN RIDGE OVER WRN NAMERICA. IT WILL BE AN ACTIVE
PERIOD WITH FREQUENT PCPN CHANCES...TYPICAL FOR THIS TIME OF
YEAR...AS THE UPPER LAKES WILL BE AFFECTED MOSTLY BY A SERIES OF
SHORTWAVES DROPPING SE INTO THE MEAN TROF. THIS PATTERN GENERALLY
DOES NOT FAVOR ANY SIGNIFICANT PCPN PRODUCING SYSTEMS. HOWEVER...IF
ANY STRONG SHORTWAVES HAPPEN TO PASS THRU THE AREA...THEY COULD BE
STRONG WIND PRODUCERS AS LATENT/SENSIBLE HEATING DUE TO THE GREAT
LAKES WILL INTENSIFY SFC WAVES.
BEGINNING THU...FCST AREA WILL BE MOSTLY BTWN SYSTEMS...ONE
SHORTWAVE MOVING FROM THE MID MISSISSIPPI VALLEY ACROSS LWR MI AND
THE NEXT SHORTWAVE TROF AND ASSOCIATED COLD FRONT SWINGING TOWARD
THE AREA FROM THE W AND NW. BULK OF THE FORCING WITH FORMER WAVE
PASSES BY TO THE SE OF THE FCST AREA...WHILE FORCING WITH LATTER
WAVE ARRIVES OVER THE WRN FCST AREA IN THE AFTN. RIGHT ENTRANCE OF
UPPER JET EXTENDING FROM FAR NRN MN TO HUDSON BAY...AND BAND OF
LOW-MID LEVEL FRONTOGENESIS SHOULD SUPPORT A BAND OF -SHRA
ALONG/JUST BEHIND COLD FRONT AS IT MOVES ACROSS THE AREA THU AFTN
THRU EARLY FRI MORNING. WITH WETBULB ZERO HEIGHTS ONLY FALLING JUST
BLO 1500FT OVER THE HIGHEST TERRAIN OF THE W...POTENTIAL FOR ANY
FROZEN PCPN IS VERY LIMITED LATE THU NIGHT/FRI MORNING.
BEHIND THE FRONT...850MB TEMPS FALL TO AROUND -3C...ON THE
THRESHOLD FOR LAKE EFFECT PCPN WITH A LARGE PORTION OF LAKE SUPERIOR
SFC WATER TEMPS AROUND 10C. HOWEVER...WITH AREAS OF WARMER WATER...
THERE IS THE POTENTIAL FOR SOME LIGHT LAKE EFFECT PCPN SIMPLY BASED
ON INSTABILTY. ON THE OTHER HAND...FCST SOUNDINGS SHOW DEVELOPMENT
OF A WELL-MIXED LAYER WHICH IS LESS FAVORABLE FOR LAKE EFFECT PCPN.
INCREASINGLY ANTICYCLONIC FLOW AS SFC HIGH PRES RIDGE BUILDS INTO
THE AREA WILL ALSO BE A NEGATIVE. SO...WILL CARRY PCPN OVER THE W IN
THE MORNING AND DIMINISH PCPN IN THE AFTN OVER THE E. WINDS CONTINUE
TO BACK A LITTLE MORE FRI EVENING AHEAD OF THE NEXT SHORTWAVE
ARRIVING FOR SAT/SAT NIGHT. SHOULD BE ABLE TO CARRY DRY FRI EVENING.
STRONGER SHORTWAVE DROPS INTO THE AREA SAT/SAT NIGHT...BRINGING
SHOWERY PCPN UNDER CYCLONIC FLOW AND PERSISTENT DEEP LAYER FORCING.
WITH 850MB TEMPS IN THE -2 TO -4C RANGE...EXPECT LAKE ENHANCEMENT.
SO PCPN WILL BE MORE LIKELY NEAR LAKE SUPERIOR. TYPICAL FOR EARLY
SEASON LAKE EFFECT...THERE WILL LIKELY BE SOME GRAUPEL WITH HEAVIER
SHOWERS...BUT BEST CHC OF ANY SNOW MIXING WITH PCPN WILL BE SAT
NIGHT/SUN MORNING OVER THE HIGHER TERRAIN. THERE WILL BE A DOWNWARD
TREND IN PCPN SUN AS SHORTWAVE DEPARTS/HEIGHTS RISE AND SUBSIDENCE
OVERSPREADS THE AREA.
UNCERTAINTY IS HIGH FOR MON/TUE AS MEDIUM RANGE GUIDANCE HAS AND
CONTINUES TO SHOW LITTLE AGREEMENT ON TIMING/STRENGTH OF SHORTWAVES
DROPPING INTO THE MEAN TROF. THERE HAVE BEEN HINTS IN SOME MODEL
RUNS IN RECENT DAYS (ECMWF IN PARTICULAR) THAT A POTENT SHORTWAVE
MIGHT DROP ACROSS THE AREA EARLY NEXT WEEK. SOMETHING TO KEEP IN
MIND IN THE COMING DAYS. IN ANY EVENT...LARGE SCALE PATTERN SUGGESTS
CONTINUED UNSETTLED WEATHER MON/TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 131 PM EDT WED OCT 16 2013
SKIES HAVE BEEN SLOW TO CLEAR ACROSS MUCH OF THE AREA THIS
AFTERNOON...HOWEVER...CEILINGS HAVE DEFINITELY IMPROVED FROM THE
IFR/LIFR CONDITIONS THAT WERE LINGERING EARLIER TODAY. VIS SATELLITE
AND UPSTREAM OBSERVATIONS INDICATE CLEARING SKIES APPROACHING THE
IWD AND CMX TAF SITES. AFTER TIMING THE APPROACH OF THE CLEARING
SKIES IT LOOKS LIKE IWD WILL CLEAR AROUND 20Z WHILE CMX MAY HOLD ON
TO CLOUD COVER THROUGH 22Z. KSAW...BEING FARTHER EAST...WILL HANG ON
TO THE CLOUD COVER THROUGH 00Z/17. CEILINGS UNDER THIS DECK OF
CLOUDS HAVE BEEN IFR TO MVFR...WITH LOWER CLOUDS REMAINING CLOSER TO
KSAW. VISIBILITY IS NOT EXPECTED TO BE A MAJOR ISSUE...HOWEVER A FEW
AREAS MAY SEE VISIBILITY SLIGHTLY REDUCED IN PATCHY DRIZZLE
LINGERING ACROSS THE AREA THIS AFTERNOON. DRIER AIR AND HIGH
PRESSURE BUILDING INTO THE REGION WILL ALLOW SKIES TO CLEAR FROM
WEST TO EAST DURING THE EVENING AND OVERNIGHT HOURS AND REMAIN THAT
WAY THROUGH THE END OF THE TAF PERIOD. WINDS SHOULD REMAIN FAIRLY
LIGHT AS THE AFOREMENTIONED HIGH PRESSURE CENTER BUILDS INTO THE
REGION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 456 AM EDT WED OCT 16 2013
LOW PRESSURE OVER EASTERN UPPER MICHIGAN EARLY THIS MORNING WILL
EXIT INTO QUEBEC BY THIS AFTERNOON. A BRIEF RIDGE OF HIGH PRESSURE
WILL PUSH ACROSS LAKE SUPERIOR LATE TODAY THROUGH TONIGHT...ALLOWING
WINDS TO DIMINISH TO LESS THAN 15 KNOTS. THE NEXT AREA OF CONCERN
WILL BE WITH A TROUGH OF LOW PRESSURE MOVING ACROSS LAKE SUPERIOR ON
THURSDAY...SHIFTING EASTWARD FRIDAY AFTERNOON...WITH ANOTHER BRIEF
RIDGE BUILDING BACK IN FRIDAY NIGHT. WINDS THROUGH THE EXTENDED
FORECAST SHOULD REMAIN BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...ROLFSON
AVIATION...KEC
MARINE...TITUS