000
FXUS63 KDTX 072305
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
605 PM EST FRI MAR 7 2014


.AVIATION...

//DISCUSSION...

COLD FRONT WILL DROP THROUGH AREA OVERNIGHT WITH A JET STREAK
BRINGING A BRIEF PERIOD OF ENHANCED FGEN IN THE 09Z-13Z TIME FRAME
PTK SOUTH. IN GENERAL...A 3-5 HOUR PERIOD OF MVFR CIGS CAN BE
EXPECTED ALONG/BEHIND THE FRONT WITH SOME -SN POSSIBLE PTK SOUTH
LATE TONIGHT WITH THE PASSAGE OF THIS JETLET. CIGS WILL LIFT ON
SATURDAY AS DRIER NORTHERLY FLOW FOLLOWS THE FRONT. SKIES WILL THEN
SCATTER OUT LATE IN THE FORECAST PERIOD HIGH PRESSURE BEGINS TO BUILD
INTO THE AREA FROM THE WEST.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE IN CEILINGS AOB 5000 FEET BETWEEN 09Z-15Z.

&&

.PREV DISCUSSION...ISSUED 322 PM EST FRI MAR 7 2014

SHORT TERM...TONIGHT

SHORTWAVE LIFTING ACROSS SOUTHERN ONTARIO NORTH OF LAKE
SUPERIOR IS SUPPORTING AN UNIMPRESSIVE AND NARROW BAND OF SNOW
EXTENDING FROM WISCONSIN INTO THE UPPER PENINSULA ALONG THE
ASSOCIATED WEAK COLD FRONT. AS THIS WAVE RACES EAST THROUGH THIS
EVENING, JET SUPPORT WILL WANE AND THE ORPHANED BAROCLINIC ZONE WILL
SAG SOUTH INTO THE CWA WHILE THE FRONTAL CIRCULATION SPINS DOWN AND
ASCENT STEADILY WANES. WITH DRY MID-LEVEL AIR IN PLACE, NOT
PARTICULARLY KEEN ON PRECIP CHANCES THIS EVENING BUT SAW NO HARM IN
LEAVING LOW CHANCE POPS IN PLACE NORTH OF I-69. LEFT SLIGHTLY HIGHER
POPS, BUT STILL IN THE CHC CATEGORY, IN PLACE SOUTH OF THE I-69 CORRIDOR
WITH ENERGY OVER THE WESTERN PLAINS THIS AFTERNOON EXPECTED TO
BECOME ENTRAINED IN THE PREVAILING SOUTHWEST FLOW LATE TONIGHT. THE
ASSOCIATED UPTICK IN MOISTURE TRANSPORT AND ISENTROPIC ASCENT ALONG
THE FRONTAL ZONE WILL PROMOTE BETTER CHANCE OF LIGHT PRECIP
DEVELOPMENT ACROSS THE SOUTHERN TWO THIRDS OF THE CWA. DESPITE
INITIALLY WARM PROFILES, WET BULBING WILL ENSURE THAT ANYTHING THAT
FALLS WILL BE FROZEN. STILL, THE WEAK NATURE OF FORCING AND PLENTY
OF DRY AIR TO OVERCOME LIMITS POTENTIAL TO A COUPLE OF TENTHS OF
SNOW AT THE VERY MOST. SLOW MOVEMENT OF THE FRONT WILL SUPPORT
OVERNIGHT LOWS NEAR 30 ACROSS THE SOUTH WHILE TEMPS FALL INTO THE
LOW TO MID 20S IN THE SAGINAW VALLEY BEHIND THE FRONT BY DAYBREAK
SATURDAY.

LONG TERM...

STRONG UPPER LEVEL WAVE CURRENTLY TRACKING ACROSS NORTHERN
ONTARIO TODAY. WEAK COLD FRONT SLOWLY CLEARING SOUTHEAST TOMORROW
MORNING WILL SUBSEQUENTLY HAVE LITTLE IN THE WAY OF UPPER LEVEL
SUPPORT. NONE-THE-LESS...A WEAK SHORTWAVE COMING OUT OF THE MIDWEST
WILL ALLOW FOR QUICK FLARE UP IN 850 MB FGEN/LOW LEVEL
CONVERGENCE...SUPPORTING HIGH CHANCE OF PRECIPITATION...SOUTH OF
M-59. 850 MB SPECIFIC HUMIDITY IS IN THE 3-4 G/KG RANGE...BUT
TEMPERATURES ARE UNFAVORABLE IN THE MID NEGATIVE SINGLE NUMBERS. IN
FACT...MOISTURE/RH QUICKLY DROPS OFF AS ONE GOES HIGHER UP...AND
THERE IS CONCERN ICE NUCLEI MAY BE LACKING...AND THUS FREEZING
DRIZZLE/LIGHT FREEZING RAIN IS A SLIGHT CONCERN. REGARDLESS...ANY
MORE SUBSTANTIAL LIFT/PRECIPITATION SHOULD SHOULD SUPPORT SNOW. ANY
ACCUMULATIONS ARE EXPECTED TO BE LESS THAN AN INCH WITH THE LESS
THAN FAVORABLE SNOW/LIQUID RATIOS AND SURFACE TEMPERATURES NEAR
FREEZING.

AMOUNT OF CLEARING SATURDAY NIGHT WILL ULTIMATELY DICTATE MINS AS
SURFACE RIDGE BUILDS INTO SOUTHERN LOWER MICHIGAN THROUGH THE
NIGHT...PROMOTING FAVORABLE RADIATION CONDITIONS. WITH DEEP SNOW
PACK IN PLACE...WILL BE GOING WITH LOWS IN THE 5 TO 15 DEGREE RANGE.
THE COLD AIR (MUCH BELOW NORMAL) LOOKS TO BE SHORT LIVED...AS RATHER
AMPLIFIED UPPER LEVEL RIDGE OVER THE NORTHERN ROCKIES INTO WESTERN
CANADA FOLDS OVER AND SPILLS SOUTH THROUGH THE SOUTHERN GREAT LAKES
SUNDAY NIGHT...AND 850 MB TEMPS ARE ADVERTISED TO RISE INTO THE MID
TO POSSIBLE UPPER SINGLE NUMBERS AHEAD OF A CLIPPER SYSTEM ON
MONDAY. THE TEMP GRADIENT IS VERY TIGHT...AND THE MAIN QUESTION IS
WHETHER LOW STRATUS DEVELOPS...(SEE NAM/GFS VS EURO)...BUT THE
POTENTIAL FOR TEMPS RISING INTO THE 40S IS THERE ONCE AGAIN...AND
WILL LEAN TOWARD THE MILDER EURO...AS NAM/GFS SEEM TO BE BIASED WITH
THE SNOW PACK/LAKE MICHIGAN INFLUENCE AND ARE LIKELY TOO MOIST AT
THE 925 MB LEVEL BOTH SUNDAY AND MONDAY.

LOW-LEVEL WARM AIR ADVECTION BENEATH THE ANTICYCLONICALLY SHEARED
SIDE OF A ZONAL UPPER LEVEL JET MONDAY WILL PROVIDE MILDER
TEMPERATURES FOR MONDAY AND TUESDAY RELATIVE TO THE WEEKEND. THIS
JET WILL PIVOT TO MORE OF A SOUTHWEST-TO-NORTHEAST ORIENTATION
TUESDAY AS LARGE-SCALE HEIGHT FALLS COMMENCE OVER THE NORTHERN
PLAINS/UPPER MIDWEST. MODELS ARE IN GENERAL AGREEMENT THAT SEVERAL
PIECES OF ENERGY IN SPLIT UPPER FLOW WILL CONSPIRE TO INDUCE
CYCLOGENESIS OVER THE SOUTHERN PLAINS BY 00Z WEDNESDAY...WITH THE
CYCLONE MOVING EASTWARD TOWARD THE EAST COAST ON WEDNESDAY.
CONFIDENCE IS LOW AS TO THE TRACK OF THIS SYSTEM...BUT FOR NOW A
TRACK TO THE SOUTH OF THE CWA SEEMS MOST LIKELY...SO HIGHEST POPS
ARE OVER THE SOUTH. TEMPERATURES TO THE NORTH AND WEST OF THE LOW
TRACK APPEAR COLD ENOUGH TO SUPPORT SNOW AS THE DOMINANT PRECIP
TYPE. THESE TEMPERATURES WILL AGAIN COOL DOWN TO SEVERAL DEGREES
BELOW NORMAL WEDNESDAY AND THURSDAY AS THE ASSOCIATED UPPER-LEVEL
TROUGH TRANSLATES ACROSS THE REGION.

MARINE...

A COLD FRONT WILL BE SLIDING THROUGH THE CENTRAL GREAT LAKES TONIGHT
INTO SATURDAY MORNING...BUT WINDS LOOK TO BE REMAINING PREDOMINATELY
BELOW 20 KNOTS...EVEN BEHIND THE FRONT ON SATURDAY. SOUTHWEST WINDS
WILL INCREASE MODERATELY SUNDAY AND MONDAY AS TWO WAVES OF LOW
PRESSURE TRACKS THROUGH SOUTHERN CANADA...BUT THE ICE COVERED LAKES
AND MILDER AIR STREAMING INTO THE AREA WILL LEAD TO STABLE NEAR
SURFACE PROFILES AND THUS LIMITING THE MIXING. A STRONG COLD FRONT
IS ON TRACK TO MOVE THROUGH ON TUESDAY...WITH ANOTHER BLAST OF COLD
AIR ARRIVING ON WEDNESDAY.

&&

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

&&

$$

AVIATION.....99
SHORT TERM...JVC
LONG TERM....SF/DT
MARINE.......SF


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