000
FXUS63 KMQT 161949
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
349 PM EDT SUN JUN 16 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 349 PM EDT SUN JUN 16 2013

THE MAIN CONCERN FOR THE SHORT TERM FORECAST WILL BE THE ONGOING
SHOWERS AND THUNDERSTORMS AND ADDITIONAL SHOWERS WITH THE TROUGH
DROPPING SOUTH ACROSS THE AREA TONIGHT. INITIAL CONVECTION WAS OVER
EASTERN UPPER MICHIGAN...WHERE THERE WAS INCREASED MOISTURE FROM THE
FOG EARLIER TODAY AND CONVERGENCE FROM WEAK LAKE BREEZES. THESE
INITIAL SHOWERS HAVE SHIFTED TO THE SOUTHEAST AND OUT OF THE
CWA...BUT ARE SEEING SOME SHOWERS IN CENTRAL UPPER MICHIGAN ALONG
THE LAKE SUPERIOR LAKE BREEZE. THESE SHOWERS HAVE BEEN LIMITED THUS
FAR DUE TO THE DRY MID LEVEL AIR EVEN THOUGH THERE IS STRONG
LOW LEVEL LAPSE RATES AND RAP ANALYZED SB CAPE VALUES OF
500-1000 J/KG. BUT WITH THE INVERTED V LOOK TO THE RAP
SOUNDINGS...ML CAPES ARE STRUGGLING TO GET MUCH ABOVE 250-500 J/KG.
THIS DRY AIR CAN ALSO BE SEEN IN THE DEWPOINTS /UPPER 40S/ AWAY
FROM THE INFLUENCE OF THE GREAT LAKES. THERE HAVE EVEN BEEN SOME
SIGNIFICANT JUMPS IN THE DEWPOINTS OVER THE EASTERN CWA...AS THE
LAKE BREEZES HAVE MOVED IN AND OUT OF SOME OF THE SITES. FARTHER
WEST...A PERSISTENT SHOWER/THUNDERSTORM CLUSTER MOVED INTO WESTERN
GOGEBIC COUNTY OVER THE LAST HOUR AND DID PRODUCE SOME GUSTS UP TO
40KTS EVEN THOUGH THE CLUSTER IS DIMINISHING. THIS ISN/T TOO
UNREASONABLE WITH CURRENT DCAPE VALUES OVER MUCH OF UPPER MICHIGAN
AROUND 800-1000 J/KG AND THE INVERTED V SOUNDINGS. WOULD EXPECT
THIS TO BE THE PRIMARY CONCERN FOR ANY SHOWERS/THUNDERSTORMS LATE
THIS AFTERNOON AND EVENING. FINALLY...ADDITIONAL
SHOWERS/THUNDERSTORMS HAVE BEEN ONGOING JUST NORTHEAST OF LAKE
SUPERIOR...DUE TO ONE PIECE OF SHEARED OFF UPPER LEVEL ENERGY
DROPPING SOUTHEAST ALONG THE TROUGH. THESE SHOWERS WILL CONTINUE
QUICKLY SOUTHEAST AS THE STORM MOTION IS AROUND 40KTS.

THE AREA THAT WILL BRING THE BEST CHANCE FOR SHOWERS IS THE
REMNANT SHORTWAVE FROM THE UPPER LOW THAT WAS IN CENTRAL
SASKATCHEWAN YESTERDAY. THIS SHORTWAVE HAS STARTED TO MOVE TOWARDS
THE CANADA/ND/MN BORDER AND HAS SPARKED SHOWERS AND THUNDERSTORMS
ALONG THE SURFACE TROUGH WHERE THERE IS DEEPER MOISTURE. WITH THE
STORM MOTION TO THE SOUTHEAST AROUND 30-35KTS AND THE TROUGH SLOWLY
SAGGING SOUTHEAST...WOULD EXPECT THOSE SHOWERS TO MOVE SOUTHEAST
ACROSS WESTERN/CENTRAL UPPER MICHIGAN LATE THIS AFTERNOON AND INTO
THE EVENING HOURS. NOT ENTIRELY CONFIDENT ON THE EASTERN CWA...AS
IT WILL DEPEND ON THE THUNDERSTORMS CURRENTLY MOVING SOUTHEAST
FROM THUNDER BAY AND HOW FAR SOUTHEAST THEY WILL MAKE IT BEFORE
DIMINISHING. WILL HAVE LOWER POPS THAN OVER THE WEST...BUT STILL
IN THE LOW END CHANCE CATEGORY. AN EARLIER UPDATE COVERED THE
TIMING WELL OVER THE WEST AND HAVE JUST MADE MINOR TWEAKS TO
MATCH THE CURRENT CONDITIONS...WITH MOST AREAS IN THE HIGHER REACHES
OF THE SCATTERED/CHANCE CATEGORY. THINK THERE IS A DECENT SHOT MOST
LOCATIONS WILL SEE RAIN...BUT THE COVERAGE/TIMING WOULD BE BETTER
REFLECTED IN THE SCATTERED WORDING. AS MENTIONED ABOVE...THE DRY
AIR AND LIMITED INSTABILITY WILL BE THE MAIN LIMITING FACTORS TO
THE THUNDERSTORMS AND THEIR SEVERE POTENTIAL. BEST THREAT WILL BE
WEST-SOUTHWEST OF THE CWA WHERE THE 850-700/500MB LAPSE RATES ARE
THE STEEPEST...BUT THERE COULD BE SOME STRONGER STORMS OVER THE
SOUTHWEST THIRD OF THE CWA. HAIL POTENTIAL WILL BE LIMITED DUE TO
THE LIMITED INSTABILITY AND TALL/SKINNY CAPE. AS MENTIONED
ABOVE...GUSTY WINDS WILL BE THE BIGGEST THREAT OVER THE SW
HALF OF THE CWA...AS THEY HAVE THE STEEPER MID LEVEL LAPSE
RATES...COMBINED WITH THE DRY LOW LEVELS TO PRODUCE THE HIGHER
DCAPE VALUES.

THEN...AS THE SHORTWAVE TRACKS SOUTHEAST INTO NORTHWEST WISCONSIN
TONIGHT AND THE REST OF NORTHERN WISCONSIN ON MONDAY
MORNING...WOULD EXPECT SCATTERED SHOWERS TO CONTINUE THROUGH THE
NIGHT OVER THE SOUTHWEST HALF OF THE CWA. THAT IS ALSO WHERE
THE BEST 850-500MB Q-VECTOR CONV IS LOCATED EVEN THOUGH THE DEEPER
MOISTURE IS OVER EASTERN UPPER MICHIGAN. HAVE SLOWLY DIMINISHED THE
THUNDER THREAT OVERNIGHT AND INTO MONDAY MORNING TO BE OVER THE
SOUTHERN PART OF THE CWA...WHERE THE BETTER FORCING IS LOCATED. WILL
HOLD ON TO SOME LIGHT RAIN SHOWERS OVER NORTHERN UPPER MICHIGAN
OVERNIGHT TONIGHT AND INTO TOMORROW MORNING...AS LOW LEVEL
CONVERGENCE INCREASES WITH THE WINDS SHIFTING TO THE
NORTH-NORTHEAST. WITH DECENT MOISTURE BELOW 10KFT AS THAT
CONVERGENCE OCCURS...THINKING THERE WILL BE ENOUGH TO PRODUCE SOME
SHOWERS...ESPECIALLY OVER SOME OF THE HIGHER TERRAIN LOCATIONS OF
NORTH CENTRAL UPPER MICHIGAN WHERE THE WINDS BECOME UPSLOPE FOR A
PERIOD OF TIME.

THE LARGER SCALE FORCING SHOULD DEPART THE SOUTHWEST AND SOUTH
CENTRAL CWA AROUND DAYBREAK AND THEY WILL BE LEFT WITH ANY SHOWERS
DROPPING SOUTH ALONG THE ENHANCED CONVERGENCE. BEHIND THE
TROUGH...LOW CLOUDS SEEN IN CENTRAL ONTARIO/MANITOBA THIS MORNING
WILL MOVE SOUTH ACROSS THE CWA LATE TONIGHT INTO TOMORROW MORNING.
MODELS STRUGGLING WITH HOW LOW THE CLOUDS WILL BE...BUT EITHER WAY
A CLOUDY START TO THE WORK WEEK IS EXPECTED. CANADIAN HIGH PRESSURE
IS EXPECTED TO BUILD OVER THE AREA ON MONDAY AFTERNOON...BRINGING
DRIER AIR AND SUBSIDENCE TO THE AREA IN THE AFTERNOON. THIS WILL
PRODUCE DECREASING CLOUDS FROM NORTH TO SOUTH. HIGHS WILL BE MUCH
COOLER TOMORROW...WITH 60S IN MOST LOCATIONS EXCEPT NEAR LAKE
SUPERIOR WHERE NORTHERLY FLOW OFF THE LAKE WILL KEEP HIGHS IN THE
UPPER 50S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 529 AM EDT SUN JUN 16 2013

THE WEATHER IN THE LONG TERM WILL NOT CHANGE DRAMATICALLY...WITH NO
SIGNIFICANT PATTERN CHANGES IN SIGHT. EXPECT 500MB LOW PRESSURE TO
REMAIN OVER NE CANADA AND HUDSON BAY THROUGH THE ENTIRE PERIOD.

WILL START OUT MONDAY WITH A GOOD AMOUNT OF CLOUD COVER...THANKS TO
COOL N FLOW OFF LAKE SUPERIOR /850MB TEMPS NEAR 7C ALONG THE SHORE/
AND THE 500MB SHORTWAVE BREAKING UP THE WEAK NW TO ZONAL FLOW. THE
SHORTWAVE WILL SLIDE IN FROM NE MN AND ONTARIO EARLY...WITH
IMPROVING CONDITIONS BY EARLY AFTERNOON. THE 500MB LOW SPINNING NEAR
JAMES BAY ON MONDAY WILL SWING ANOTHER WAVE DOWN FROM ONTARIO MONDAY
NIGHT...WITH VERY LITTLE IMPACT AS HIGH PRESSURE DOMINATES AT THE
SFC. FEW CLOUDS...LIGHT WINDS...AND COOL TEMPS FALLING INTO THE LOW
TO MID 30S SHOULD BE ENOUGH FOR PATCHY FROST ACROSS THE INTERIOR W
HALF OF UPPER MI AFTER MIDNIGHT MONDAY NIGHT INTO EARLY TUESDAY
MORNING.

DRY WEATHER SHOULD THEN BE THE RULE THROUGH AT LEAST WEDNESDAY...AS
THE SFC HIGH SLOWLY SINKS ACROSS LOWER MI. EXPECT A SLOW AND STEADY
WARMUP EACH DAY...WITH LAKE BREEZES LIKELY EACH AFTERNOON...COOLING
DOWN NEAR SHORE AREAS. WAA WILL INTENSIFY WEDNESDAY...WITH 850MB
TEMPS RISING TO AROUND 10C BY THE END OF THE DAY.

THERE COULD BE A SMALL CHANCE OF SHOWERS WEDNESDAY NIGHT INTO EARLY
THURSDAY MORNING...OR MORE THAN LIKELY JUST INCREASED CLOUD
COVER...ASSOCIATED WITH YET ANOTHER WAVE SWEEPING ACROSS THE UPPER
GREAT LAKES ON OUR QUICK NW FLOW ALOFT.

ALTHOUGH IT LOOKS LIKE A PRETTY WET PERIOD POP WISE FOR WEDNESDAY
NIGHT THROUGH SUNDAY...IT WILL BE A LOW CONFIDENCE FORECAST BEYOND
THIS PERIOD. THE CONSENSUS IS TO CONTINUE TO KEEP THE FAR EASTERN
AREAS A BIT DRIER...WITH A SFC LOW ORGANIZING ACROSS THE PLAINS
STATES FOR THE END OF THE WORK WEEK. THE BEST DYNAMICS LOOK TO STAY
TO OUR SOUTH...AS THE SFC LOW SLIDES TOWARD LAKE MI AND LOWER MI
SATURDAY NIGHT. IF THAT OCCURS...IT WILL GIVE THE EAST END OF UPPER
MI A GOOD CHANCE OF RECEIVING A WETTING RAIN.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 136 PM EDT SUN JUN 16 2013

AN UPPER LEVEL DISTURBANCE WILL COMBINE WITH A SURFACE TROUGH
DROPPING SOUTH ACROSS LAKE SUPERIOR TO PRODUCE SHOWERS AND SOME
THUNDERSTORMS FOR ALL TAF SITES THIS AFTERNOON INTO TONIGHT. DRY AIR
CURRENTLY OVER UPPER MICHIGAN HAS BEEN KEEPING THE DIURNAL CU IN
CHECK SO FAR THIS AFTERNOON. BUT AS THE DISTURBANCE NEARS OVER THE
NEXT FEW HOURS...THE POTENTIAL FOR SHOWERS WILL BE ON THE INCREASE.
THEY SHOULD AFFECT KCMX/KIWD FIRST AS THEY QUICKLY SLIDE SOUTHEAST
FROM THE MN ARROWHEAD. WILL HOLD OFF ON THUNDER MENTION FOR ALL BUT
KIWD DUE TO UNCERTAINTY IN TIMING/LOCATION OF THE SHOWERS. FELT
CONFIDENT ENOUGH WITH A LINE OF SHOWERS/THUNDERSTORMS NEARING DULUTH
TO MENTION THUNDER AT KIWD...BUT LEFT OUT OTHERWISE. THE SCATTERED
SHOWERS/THUNDERSTORMS WILL SPREAD SOUTHEAST THROUGH THE REST OF THE
EVENING...AS THE FRONT AND SHORTWAVE PASS THROUGH THE AREA.

OVERNIGHT...EXPECT THE THUNDER THREAT TO DIMINISH AND SLIDE
SOUTH. MEANWHILE...LIGHT NORTHERLY FLOW BEHIND THE SFC TROUGH WILL
TRY TO PULL LOW CLOUDS INTO THE AREA. THESE CLOUDS HAVE BEEN SEEN
OVER SOUTHERN ONTARIO TODAY...BUT THE MODELS HAVE BEEN VARYING ON
IF THEY WILL OCCUR LATE TONIGHT INTO TOMORROW MORNING. TO
COMPLICATE MATTERS...SOME FOG LINGERS OVER EASTERN LAKE
SUPERIOR...WHICH COULD SHIFT TOWARDS KSAW/KCMX WITH THE WINDS SHIFT
AND ADDITIONAL MOISTENING FROM THE SHOWERS. SINCE IT IS LATER IN
THE PERIOD...OPTED TO PLAY THE MIDDLE GROUND AT THIS POINT /MVFR
CEILINGS/ BUT IFR OR LOWER CEILINGS/VISIBILITY IS POSSIBLE AT
KCMX/KSAW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 PM EDT SUN JUN 16 2013

WINDS ARE EXPECTED TO STAY BELOW 20KTS THROUGH THE PERIOD. A TROUGH
WILL DROP SOUTH ACROSS LAKE SUPERIOR THIS EVENING...LEADING TO WINDS
SHIFTING TO THE NORTH TONIGHT. AS THE TROUGH CONTINUES SOUTHEAST ON
MONDAY...HIGH PRESSURE WILL BUILD OVER THE UPPER GREAT LAKES AND
REMAIN THROUGH WEDNESDAY. A WEAK TROUGH WILL THEN APPROACH THE AREA
FROM THE NORTHWEST FOR THURSDAY. THERE IS A POCKET OF FOG OVER
EASTERN LAKE SUPERIOR /NEAR AND EAST OF GRAND MARAIS MI/ THAT HAS
BEEN DIMINISHING AND MOVING AROUND TODAY. WOULD EXPECT THE DRY AIR
TO CONTINUE TO EAT AWAY AT IT THIS EVENING...BUT THERE IS SOME
CONCERN IT COULD EXPAND WITH RAIN OCCURRING OVER CENTRAL LAKE
SUPERIOR THIS AFTERNOON/EVENING AND LINGER THROUGH THE NIGHT.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KF
AVIATION...SRF
MARINE...SRF