000
FXUS63 KMQT 182048
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
448 PM EDT SAT MAY 18 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 446 PM EDT SAT MAY 18 2013

PRECIP OVER THE NRN HALF OF THE CWA THIS AFTERNOON IS BEING DRIVEN
BY MOISTURE TRANSPORT/WAA BEHIND AN 850MB WARM FRONT THAT IS
APPROACHING NERN LAKE SUPERIOR. SLY FLOW BEHIND THE FRONT BETWEEN
DEVELOPING LOW PRESSURE OVER THE PLAINS AND HIGH PRESSURE OVER
QUEBEC WILL CONTINUE TO STREAM WARMER TEMPS AND MOISTURE INTO THE
CWA TONIGHT...WHILE THE 850MB WARM FRONT STALLS OUT OVER THE NRN
CWA. THE FRONT STAYING OVER THE NRN CWA INTO TONIGHT WILL KEEP
PRECIP CHANCES HIGHEST OVER THE KEWEENAW PENINSULA...WITH LITTLE TO
NO PRECIP EXPECTED ELSEWHERE.

WITH 850MB TEMPS AROUND 14C SUN...AND LESS LOW LEVEL MOISTURE THAN
THE GFS/NAM SHOW AS HAS BEEN THE CASE LATELY...EXPECT HIGH TEMPS
AROUND 80 AWAY FROM MODERATING LAKE SUPERIOR. THE SYSTEM OVER THE
PLAINS WILL WRAP UP OVER SD BY 00Z MON WHILE SFC HIGH PRESSURE MOVES
FROM THE NRN TERRITORIES OF CANADA NOW TO NRN ONTARIO BY 00Z MON.
WITH THE SFC HIGH SLIDING TOWARD THE AREA BEHIND AN UPPER TROUGH AND
THE LOW CLOSING OFF TO THE W...EXPECT A SFC TROUGH TO SLIDE INTO THE
CWA LATER SUN. THIS WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS
TO MOVE BACK INTO THE WRN HALF OF THE CWA BY LATE SUN. FOR THE MOST
PART...GENERAL THUNDER IS EXPECT...BUT CAN NOT COMPLETELY RULE OUT A
STRONGER STORM OR TWO ALONG THE WI BORDER WITH 500-1000J/KG OF CAPE
AND AROUND 30KTS OF 0-6KM BULK SHEAR ALONG THE SRN CWA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 446 PM EDT SAT MAY 18 2013

SUNDAY NIGHT...ALTHOUGH THERE WERE SOME DIFFERENCES...THE MODELS
WERE IN GENERAL AGREEMENT WITH THE POSITION OF THE MID LEVEL LOW
MOVING INTO CNTRL NEBRASKA AND THE SFC LOW TO SE SD BY 12Z MON. THE
SFC WARM FRONT WILL STRENGTHEN ACROSS SRN MN INTO SRN WI. EXPECT THAT
PCPN WILL INCREASE/EXPAND ACROSS THE WEST/CNTRL CWA WITH MOISTURE
INFLOW AND 300K-310K ISENTROPIC ASCENT ALONG THE 850-700 MB FRONT.
ALTHOUGH THE GREATEST INSTABILITY TO SUPPORT TSRA WILL REMAIN TO THE
SOUTH...SOME EMBEDDED ELEVATED CONVECTION WILL BE POSSIBLE.

MON INTO MON NIGHT...AS THE MID LEVEL LOW REMAINS NEARLY STATIONARY
OR MOVES SLIGHTLY TO THE EAST AND UPPER LEVEL DIV/700-300 MB QVECTOR
CONV FORCING FOR LARGE SCALE ASCENT REMAINS OVER THE AREA...SMALLER
SCALE SHORTWAVES MOVING THROUGH THE AREA WILL SUPPORT PERIODS OF RAIN
SHOWERS. HEAVY RAINFALL AMOUNTS OF 1 TO 2 INCHES REMAIN POSSIBLE WITH
ABUNDANT MOISTURE AVAILABLE (PWAT VALUES TO AROUND 1.5 INCHES...200
PERCENT OF NORMAL). ELEVATED TSRA CHANCES ALSO CONTINUE WITH MUCAPE
VALUES IN THE 500-1000 J/KG. CLOUD COVER AND PCPN WILL KEEP TEMPS
MAINLY TOWARD THE LOWER END OF GUIDANCE...ESPECIALLY DOWNWIND FROM
ERLY FLOW OFF OF THE GREAT LAKES.

TUE-WED...MODELS SUGGEST THAT THE BLOCKING/STAGNANT PATTERN WITH A
PROMINENT RIDGE OVER S CNTRL CANADA WILL FAVOR CONTINUED SLOW
PROGRESSION OF THE MID LEVEL LOW TO THE NE TO AROUND SE MN OR WRN WI
BY 00Z THU. SO...LIKELY OR HIGHER END CHANCE PCPN POPS WILL
CONTINUE. PCPN...THICKER CLOUDS AND PCPN WILL KEEP TEMPS BELOW
NORMAL.

THU-SAT...ALTHOUGH THE 00Z/12Z ECMWF WAS THE MOST AGGRESSIVE IN
BRINGING THE AREA UNDER THE INFLUENCE OF NW FLOW DOWNSTREAM FROM THE
BLOCKING RIDGE...THE GFS AND GFS ENSEMBLES ALSO HAVE TRENDED TOWARD
THAT SCENARIO. THIS WOULD FINALLY BRING DRIER AND COOL AIR INTO THE
REGION WITH TEMPS REMAINING BELOW NORMAL AS HIGH PRES BUILDS INTO THE
NRN GREAT LAKES FROM NRN ONTARIO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 146 PM EDT SAT MAY 18 2013

A WARM FNT MOVING IN FM THE SOUTH WILL BRING SOME -SHRA/MVFR CIGS
/LIFR CIGS AT CMX WITH UPSLOPE FLOW/...MAINLY AT IWD/CMX WHERE LLVL
WARM/MOIST ADVCTN WL BE MOST PRONOUNCED. MOIST UPSLOPE FLOW OFF LK
SUPERIOR MAY RESULT IN IFR CONDITIONS INTO THIS EVENING. FOLLOWING
THE WARM FROPA TONIGHT...EXPECT WSHFT TO THE S WITH RETURN TO
PREDOMINANT VFR WX. THE ONLY EXCEPTION WL BE AT CMX...WHERE
PERSISTENT UPSLOPE ESE WIND AND MOISTER LLVL AIR WL RESULT IN
LINGERING MVFR CONDITIONS THROUGH MUCH OF THE NIGHT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS. THE LOW PRESSURE SYSTEM
WILL SLIDE SOUTH OF LAKE SUPERIOR WED...BUT THE PRESSURE GRADIENT
WILL BE WEAKER THAN EARLIER IN THE WEEK...SO LIGHTER ELY WINDS ARE
EXPECTED.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...TITUS
MARINE...TITUS