Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 220656
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
256 AM EDT TUE JUL 22 2014

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 256 AM EDT TUE JUL 22 2014

...A COUPLE OF CHANCES FOR THUNDERSTORMS...

IMPACTS: LIGHTNING FROM THUNDERSTORMS. SEVERE THREAT MINIMAL...BUT
MAIN THREAT IS WIND. GREAT LAKES FOG.

CURRENT WEATHER AND SYNOPTIC PATTERN:

NOW WE ARE STARTING TO GET CLOSER TO ALL THE ACTION...AFTER SEVERAL
DAYS OF INCREASINGLY MORE SUMMER-LIKE WEATHER. LOOKING AT UPSTREAM
CONDITIONS...MORE SUMMER CAN BE EXPECTED HEADING THROUGH TODAY AND
TONIGHT. ACROSS NRN MN RESIDES A POTENT LITTLE SHORTWAVE/VORT MAX
AND ASSOCIATED SFC LOW PRESSURE...WITH A COLD FRONT DRAPING SW AND
INTO SD/NE. AHEAD OF THIS FRONT AND SFC LOW...IS A 40-50KT H8 LLJ
AND AXIS OF MAX THETA-E/INSTABILITY. AN MCS WAS EARLIER PRODUCING
SPORADIC DAMAGING WINDS (50KT MID LEVEL JET) WHILE FEEDING ON THIS
MOISTURE AND INSTABILITY. HOWEVER...THE STORM COMPLEX WAS WEAKENING
AS IT HAS ENCOUNTERED A MORE CAPPED ATMOSPHERE TO ITS EAST IN
WISCONSIN. THE 00Z APX SOUNDING SHOWS OUR STRONGLY CAPPED
ATMOSPHERE...MAXED AROUND 750MB. WE WERE VERY MILD WITH CONTINUED
LOW TO MID LEVEL WARM ADVECTION. EVEN WITH CLEAR SKIES...ALL AREAS
WERE BASICALLY IN THE 60S.

SYNOPTIC PATTERN/WEATHER EVOLUTION:

THROUGH MORNING...WE DO CONTINUE TO MOISTEN THE LOW LEVELS...BUT
BEST THETA-E ADVECTION AND LLJ FORCING ALL LIFT TO OUR NORTH.
CONSIDERING THE STRONG CAPPING IN PLACE...GOTTA BELIEVE THAT THE
UPSTREAM MCS WILL NOT AFFECT NRN LOWER...BUT MAYBE SOME REMNANT
SHOWERS/STORMS CAN ROLL THROUGH EASTERN UPPER. THIS IS PRETTY LOW
CHANCE THOUGH. THE SHORTWAVE WILL WANT TO SHEAR OUT AND TRACK A BIT
FURTHER NORTH INTO THE DAY...WHILE DRAGGING THE SFC COLD FRONT INTO
EASTERN UPPER AROUND 21Z AND ACROSS NRN LOWER 00-03Z. THIS IS THE
RIGHT TIME FOR PEAK HEATING/MAX INSTABILITY...WHICH RANGES FROM
SEVERAL HUNDRED J/KG NORTH...TO AS MUCH AS 1800 J/KG SOUTH. PURE
DIABATIC HEATING DOESN`T LOOK TO GET PAST THE CAP...BUT WITH THE
ARRIVAL OF THE FRONT AND SHORTWAVE...CAN BUY INTO SCATTERED SHOWERS
AND SOME STORMS ROLLING ON THROUGH. MOST OF THE INSTABILITY WILL BE
WELL SOUTH AND WEST OF US...AND WOULD REALLY LIKE TO SEE SOME BETTER
COOLING/STEEPER LAPSE RATES ALOFT. THE SHEARING OUT WAVE DOESN`T
HELP MUCH HERE. THERE ARE DEFINITE DIFFERENCES IN DATA BETWEEN HOW
MUCH OF THE CAP CAN BE ERODED...SOME DATA SUGGESTING THAT THE CAP
PLAYS A MAJOR ROLE IN REALLY LIMITING WHAT WE CAN ATTAIN AS FAR AS
CONVECTION. A MORE REALISTIC IDEA WITH THIS SETUP/ENVIRONMENT IS FOR
AT LEAST SOME SCATTERED ACTIVITY ALONG AND AHEAD OF THE FRONT WITH
JUST AN OUTSIDE SHOT AT SOME DAMAGING WINDS...AND TO A LESSER DEGREE
SEVERE HAIL. ONCE AGAIN...IT APPEARS AS THOUGH THE AMOUNT OF
INSTABILITY WILL WILL NOT BE ENOUGH TO GENERATE STRONG ENOUGH
UPDRAFTS TO SUPPORT ANY SIGNIFICANT HAIL...OR TO TAP INTO RATHER
MINIMAL 40-45KT MID LEVEL WINDS. SEVERE THREAT IS MINIMAL.

FRONT CLEARS NE LOWER/SAG BAY AREA AROUND 03Z....WITH STRONG DRYING
AND COOLING BEHIND IT. NORTHERLY FLOW TO NEAR 750MB WITH PWATS
FALLING FROM 1.70" TO NEAR 0.50". SHOULD CLEAR PRETTY WELL WITH
MAYBE SOME SCATTERED LOWER CLOUDS (FCST BFR SOUNDINGS SUGGEST MORE
SOLID STRATUS...BUT THIS IS DOUBTFUL).

HIGH TEMPS IN THE LOWER 80S EASTERN UPPER/85-90 IN NRN LOWER. LOWS
TONIGHT LOW 60S SOUTHEAST...BUT FALLING INTO THE 50S ELSEWHERE.

&&

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 320 PM EDT MON JUL 21 2014

HIGH IMPACT WEATHER POTENTIAL: THUNDERSTORM POTENTIAL TUESDAY.

PATTERN SYNOPSIS/FORECAST: RIDGE EXTENDS FROM NEW MEXICO INTO THE
GREAT LAKES. STRONG SHORTWAVE SOUTH OF ALASKA MOVING ALMOST DUE
SOUTH TOWARDS PACIFIC NW. TROUGH IN THE EASTERN U.S.

OVER THE FORECAST PERIOD...SLOW MOVING PACIFIC NW SHORTWAVE WILL
FORCE THE RIDGE OVER MIDDLE OF THE U.S. TO PINCH/RETROGRADE WEST
DURING THE DAY TUESDAY. ENERGY DROPPING OVER TOP OF THE RIDGE
/ENHANCED BY RIGHT ENTRANCE REGION OF 110KT UPPER JET/ DROPS INTO
HUDSON BAY HELPING TO DEVELOP A QUICK MOVING TROUGH ACROSS THE GREAT
LAKES WEDNESDAY INTO THURSDAY. AS THE PACIFIC NW SHORTWAVE GETS
CAUGHT IN THE WESTERLIES IT MOVES SLOWLY TO THE EAST...FORCING THE
NORTHERN EDGE OF THE RIDGE OVER THE LAKES EARLY IN THE WEEKEND. THAT
SAME SHORTWAVE THEN DROPS INTO THE REGION SUNDAY...AND CARVES OUT A
DEEPER AND MORE PERSISTENT TROUGH OVER THE EASTERN US FOR EARLY NEXT
WEEK.

PRIMARY FORECAST CONCERNS (NEAR TERM): THUNDERSTORMS FOR TUESDAY
INTO TUESDAY NIGHT.

NEAR TERM (TUESDAY): HOT. TEMPERATURES WILL MAKE A RUN AT 90 DEGREES
/FIRST TIME FOR MOST AREAS THIS SUMMER/ WITH 850MB TEMPS IN THE
UPPER TEENS ACROSS NORTHERN LOWER AHEAD OF APPROACHING COLD FRONT.
CONVECTION FROM MINNESOTA MCS EXPECTED TO DROP SOUTHEAST...WEST OF
OUR REGION. MEANWHILE BEST DYNAMICS MOVE NORTH OF REGION IN RIGHT
ENTRANCE REGION OF UPPER JET/UPPER DIVERGENCE. INSTABILITY FROM
WARMING LOW LEVELS WILL BE OFFSET BY WARMING MID LEVELS. BUFKIT
SOUNDINGS SHOW CAPE VALUES PEAKING AROUND 700J/KG IN THE
AFTERNOON/EVENING...BUT WILL NEED TO OVERCOME CIN VALUES OF
100-200J/KG DURING THE DAY AND AFTERNOON. BEST LOW LEVEL MOISTURE
WILL LIKELY STAY SOUTH OF THE REGION. MAY BE SOME HIGH CLOUDINESS
FROM MCS EARLY IN THE DAY BUT LITTLE ELSE. PRECIPITATION CHANCES
INCREASE AS FRONT GET CLOSER AND MOVES THROUGH IN THE LATE EVENING
HOURS.

REST OF THE FORECAST (WEDNESDAY THRU MONDAY): AS RIDGING RE-
ESTABLISHES ITSELF EXPECT ANOTHER EXTENDED STRETCH OF DRY WEATHER
INTO THE WEEKEND. TEMPERATURES QUITE COOL ON WEDNESDAY WITH SLOW
WARM UP TO END THE WEEK. NEXT TROUGH ARRIVES THIS WEEKEND...WITH
SHORTWAVE/FRONTAL SYSTEM APPROACHING THE GREAT LAKES SUNDAY INTO
MONDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM EDT MON JUL 21 2014

VFR THRU AT LEAST MID-AFTERNOON...THEN CHANCES FOR BRIEF
RESTRICTIONS IN TSRA INTO MID-EVENING. LLWS OVERNIGHT MBL/PLN/TVC.

LOW PRESSURE WILL ADVANCE FROM FAR NW MN...CROSSING LAKE SUPERIOR
TUE AFTERNOON. A NON-ZERO CHANCE FOR SOME FOG VERY LATE TONIGHT...
BUT FOG HAS BECOME LESS WIDESPREAD OVER THE LAST FEW NIGHTS...
SUGGESTING A MINIMAL THREAT AT BEST. A PRECIP THREAT WILL HOLD OFF
UNTIL LATE TUESDAY AFTERNOON...BUT AS A COLD FRONT MOVES IN TSRA
ARE A POTENTIAL (THOUGH NOT CERTAIN) PROBLEM LATE AFTERNOON TIL
MID EVENING.

LIGHT WINDS TONIGHT...BREEZY S TO SW WINDS DEVELOPING TUESDAY. SW
WINDS WILL INCREASE JUST OFF THE DECK TONIGHT...AND HAVE MENTIONED
LLWS MENTION AT MBL/TVC/PLN.


&&

.MARINE...
ISSUED AT 256 AM EDT TUE JUL 22 2014

LOW PRESSURE AND A COLD FRONT WILL CROSS THE NEARSHORE WATERS THIS
AFTERNOON THROUGH THIS EVENING. THE PRESSURE GRADIENT STRENGTHENS
AHEAD OF THE FRONT AND IS THE REASON FOR THE CURRENT LAKE MICHIGAN
ADVISORIES. THIS STILL LOOKS GOOD WITH 35-40KTS S/SW FLOW OFF THE
SFC...DESPITE STABILITY CONCERNS. MORE ADVISORIES NOW POSTED THROUGH
WEDNESDAY MORNING FOR THE REMAINDER OF THE NEARSHORES. THIS IS DUE
TO STRONG COLD ADVECTION/SLIGHTLY UNSTABLE CONDITIONS DEVELOPING...A
PERIOD OF 30-35KT NW/N LOW LEVEL WINDS JUST ABOVE THE WATER
SFC...AND RESULTANT CHOPPY WAVES.

WINDS WEAKEN AND BACK MORE WESTERLY INTO THURSDAY AS HIGH PRESSURE
BEGINS TO SETTLE IN.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT
     WEDNESDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT
     WEDNESDAY FOR LMZ323.
     SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EDT
     WEDNESDAY FOR LMZ341-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT
     WEDNESDAY FOR LSZ321-322.

&&

$$

SHORT TERM...SMD
LONG TERM...KF
AVIATION...JZ
MARINE...SMD





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