Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 060805
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
305 AM EST FRI MAR 6 2015

.SHORT TERM...TODAY AND TONIGHT

HIGH PRESSURE DRAPED ACROSS THE SOUTHEAST UNITED STATES COUPLED WITH
LOW AMPLITUDE NORTHWEST FLOW ALOFT WILL FACILITATE PERSISTENCE OF
DRY CONDITIONS THROUGH THE FORECAST PERIOD AND A CONTINUATION OF
SOUTHWEST GRADIENT FLOW. ONGOING LIGHT WARM ADVECTION WILL WARM
925MB TEMPERATURES BY 10 OR MORE DEGREES OVER THE NEXT 24 HOURS,
ENSURING HIGH TEMPERATURES IN THE MID 20S, OR ABOUT 5 TO 10 DEGREES
WARMER THAN YESTERDAY. MORE POTENT ENERGY LOCATED WELL UPSTREAM WILL
ENCROACH ON THE GREAT LAKES OVERNIGHT. STRENGTHENING SOUTHWEST
GRADIENT WILL FORCE A GRADUAL RISE IN TEMPERATURES OVERNIGHT. NO
ARGUMENTS FROM 00Z GUIDANCE THAT INDICATE TEMPERATURES BOTTOMING OUT
AROUND 20 EARLY BEFORE RISING BACK INTO THE MID 20S BY SUNRISE
SATURDAY. NOTHING MORE THAN EPISODIC MID/HIGH CLOUDS EXPECTED
THROUGH THE DAYLIGHT HOURS BEFORE BETTER LOW-LEVEL MOISTURE LOWERS
THE CLOUD DECK AFTER SUNSET.

&&

.LONG TERM...

LOWER AMPLITUDE MID LEVEL NORTHWEST WILL DEFINE CONDITIONS LOCALLY
THROUGH THE UPCOMING WEEKEND.  WEAK SHORTWAVE ENERGY ORIGINATING
FROM THE GULF OF ALASKA WILL SHEAR INTO THIS FLOW OVER THE NEXT 48
HOURS...TRANSLATING ACROSS SE MICHIGAN ON SATURDAY. CORRIDOR OF WARM
AIR ADVECTION WILL EMERGE IMMEDIATELY IN ADVANCE OF THE HEIGHT
FALLS...PROMPTING A SOLID UPWARD ADJUSTMENT IN TEMPERATURES RELATIVE
TO TODAY.  EXTENSIVE CLOUD COVER WILL DAMPEN THE RESPONSE TO SOME
DEGREE...BUT A MODESTLY MIXED ENVIRONMENT THROUGH 925 MB /-2 TO -3C/
SUPPORTS HIGHS OF MID-UPPER 30S.  BRIEF SHOT OF ISENTROPIC ASCENT ON
THE FRONT END AND A LATE DAY COLD FRONTAL PASSAGE WARRANTS A LOW END
POP MENTION THROUGHOUT THE DAY...BUT THE LIMITED MOISTURE QUALITY
AND LACKLUSTER FORCING WILL SEEMINGLY RESTRICT PRECIPITATION
CHANCES.  ENSUING WEAK COLD AIR ADVECTION INTO SATURDAY NIGHT...THE
PROCESS PERHAPS YIELDING A FEW FLURRIES AS MOISTURE BRIEFLY DEEPENS
WITH THE PASSING 850-925 MB FRONTAL SLOPE.  THIS FRONTAL ZONE WILL
TEMPORARILY SETTLE JUST TO THE SOUTH BY SUNDAY MORNING...PROVIDING A
WINDOW OF OPPORTUNITY FOR SOME CLEARING OVERNIGHT.  GOING FORECAST
LEANING TOWARD THE COLDER END OF GUIDANCE FOR LOWS SUNDAY
MORNING...LATEST MODEL EVIDENCE PROVIDING LITTLE EVIDENCE TO MOVE
AWAY FROM THIS POSITION /UPPER TEENS TO LOWER 20S/.

FRONTAL ZONE WILL WASH BACK EASTWARD AND ACROSS SE MICHIGAN ON
SUNDAY AS THE MASS FIELDS REORIENT AGAIN WITH THE APPROACH OF
ANOTHER WEAK SHORTWAVE.  CLOUDS WILL LIKELY REMAIN PROBLEMATIC
ACCOUNTING FOR BOTH THE FROPA AND A BRIEF UPTICK IN CVA WITH THE
SHORTWAVE ITSELF.  ONCE AGAIN...MOISTURE WILL BE LACKING TO SUGGEST
ANYTHING MORE THAN A LOWER END PROBABILITY FOR A FEW SNOW SHOWERS TO
DEVELOP.  A MODERATING THERMAL PROFILE WILL AGAIN SUPPORT HIGHS OF
MIDDLE 30S.

THE EXISTING TROUGHING WILL EASE EARLY NEXT WEEK...INCREASING DEPTH
TO THE LOW LEVEL WEST-SOUTHWEST FLOW ESTABLISHING A FIRM PERIOD OF
WARM AIR ADVECTION.  THE MAGNITUDE AND DURATION OF THIS WARM UP
STILL CARRIES SOME UNCERTAINTY YET AT THIS TIME SCALE...00Z GFS
CONSIDERABLY MORE PROGRESSIVE WITH THE NEXT INBOUND HEIGHT FALL
CENTER AND STRONGER FRONTAL PASSAGE /WEDNESDAY/ RELATIVE TO THE
ECMWF AND CANADIAN /FOLLOWING WEEKEND/.  REGARDLESS...LOOKING AT A
STRETCH OF SEASONABLE CONDITIONS THROUGH AT LEAST THE MIDWEEK
PERIOD.

&&

.MARINE...

SOUTHWEST FLOW WILL STRENGTHEN TODAY THROUGHOUT THE CENTRAL GREAT
LAKES.  A FIRM SOUTHWEST GRADIENT REACHING 25 TO 30 KNOTS WILL EXIST
ACROSS PORTIONS OF CENTRAL LAKE HURON THIS AFTERNOON AND EARLY
EVENING. THIS WILL BRING THE POTENTIAL FOR A BRIEF PERIOD OF
GALES. HOWEVER...THE COMBINATION OF A LIMITED DURATION...MARGINAL
MAGNITUDE AND THE FACT THAT A MAJORITY OF THE LAKE REMAINS ICE
COVERED WILL PRECLUDE THE ISSUANCE OF A GALE WARNING FOR TODAY.
PRESSURE GRADIENT WILL EASE INTO TONIGHT...WITH THE ARRIVAL OF
WARMER AIR PROVIDING AN INCREASING STABLE ENVIRONMENT HEADING INTO
THE WEEKEND. MODEST SOUTHWEST FLOW IN PLACE SATURDAY IN ADVANCE OF
A COLD FRONT. WEAK SURFACE RIDGING THEN YIELDS A WEAKER WESTERLY
FLOW FOR SUNDAY.

&&

.AVIATION...ISSUED 1143 PM EST THU MAR 5 2015

A BROAD AREA OF SURFACE HIGH PRESSURE WILL SLIDE TOWARD THE ATLANTIC
AND GULF COASTS FRIDAY AND FRIDAY NIGHT...MAINTAINING FAVORABLE
AVIATION CONDITIONS THROUGH MUCH OF THE PERIOD. ON THE BACKSIDE OF
THE HIGH...WIND SPEEDS WILL INCREASE FRIDAY AFTERNOON AS GUSTS PUSH
TOWARD 25 KNOTS UNDER THICKENING HIGH AND MID LEVEL CLOUDS.

//DTW THRESHOLD PROBABILITIES...

* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FT FRIDAY NIGHT.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...JVC
LONG TERM....MR
MARINE.......MR
AVIATION.....KURIMSKI


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