National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDTX 031100
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
600 AM EST MON MAR 3 2014


.AVIATION...

//DISCUSSION...

THERE HAS BEEN ENOUGH MOISTURE FLUX OFF ICY LAKE HURON TO LEAD TO AN
EXPANDING REGION OF MVFR BASED STRATUS. THESE CLOUDS ARE BEING
DUCTED INTO SE MI UNDERNEATH A DEEP LOW LEVEL INVERSION WITHIN NE
LOW LEVEL FLOW. SATELLITE TRENDS SUGGEST THESE CLOUDS ARE ON TARGET
TO IMPACT PTK AND POSSIBLY FNT. DAYTIME MIXING SHOULD QUICKLY ERODE
THESE CLOUDS BY AFTERNOON IN LIGHT OF THE EXTREMELY DRY AMBIENT
ARCTIC AIRMASS.

FOR DTW...THE EXPECTATION IS THAT SOME OF THE LOW STRATUS WILL
IMPACT PORTIONS OF METRO DETROIT THIS MORNING ONCE THE ONSET OF
DAYTIME HEATING GETS UNDERWAY. THE DURATION OF CLOUD COVER SHOULD BE
BRIEF IN LIGHT OF THE DRY AIR.

//DTW THRESHOLD THREATS...

* LOW CONFIDENCE IN CEILINGS BELOW 5000 FT THIS MORNING.

&&

.PREV DISCUSSION...ISSUED 332 AM EST MON MAR 3 2014

SHORT TERM...TODAY AND TONIGHT

THE PERSISTENT COLD WILL ONCE AGAIN BE THE MAIN WEATHER HEADLINE
TODAY. SFC WINDS SHOULD CONTINUE TO GRADUALLY WEAKEN EARLY THIS
MORNING AS ARCTIC HIGH PRESSURE NUDGES INTO LOWER MI FROM THE WEST.
THE LINGERING HIGH CLOUDS ACROSS THE SRN PORTIONS OF THE AREA WILL
ALSO PUSH OFF TO THE EAST BY DAYBREAK. THIS WILL SUPPORT MORNING
LOWS NEAR ZERO TO WELL BELOW ZERO. ONGOING LOW LEVEL COLD AIR
ADVECTION UNDER N-NE FLOW IN ADVANCE OF THE SFC HIGH WILL DROP 925MB
TEMPS INTO THE LOW -20S TODAY. THE NAM AND HRR SUGGEST LIMITED
SHALLOW MIXING AND POTENTIAL DAYTIME STRATO CU IN THIS AIRMASS WILL
HOLD MAX TEMPS IN THE SINGLE DIGITS. RECENT SATELLITE DATA HAS SHOWN
AN EXPANSION OF STRATO CU OVER LAKE HURON. WHILE THIS DOES SUGGEST
AN EXPANSION OF STRATO CU LATER IN THE MORNING AS THE FLOW TURNS NE
OFF LAKE HURON...EXTREMELY DRY AIR ATOP THE SHALLOW INVERSION
SHOULD ALLOW ANY LOW CLOUDS TO MIX OUT FAIRLY EARLY. THIS
EXPECTATION WILL LEND SUPPORT TO THE WARMER MAV TEMPS /AROUND 10
ABOVE TO THE MID TEENS/. THIS OF COURSE IS STILL 25 TO 30 DEGREES
BELOW EARLY MARCH NORMS AND WILL CHALLENGE RECORD LOW MAX TEMPS FOR
MARCH 3RD /12 AT DTW...16 AT FNT AND 13 AT MBS/.

THE SFC HIGH WILL BE PARKED OVER SRN MI THIS EVENING...ALLOWING A
RAPID DROP IN TEMPS TO SUB ZERO READINGS BY LATE EVENING. MID/HIGH
CLOUDS WILL THEN BE ON THE INCREASE AFTER MIDNIGHT...CAUSING A SLOW
RISE IN TEMPS TOWARD TUES MORNING. THIS INCREASE IN CLOUDS WILL
OCCUR WITHIN A BROAD REGION OF MID LEVEL WARM AIR ADVECTION
PRECEDING A FAST MOVING MID LEVEL IMPULSE ACROSS THE UPPER MIDWEST.
ENTRANCE REGION UPPER JET DYNAMICS WILL SUPPORT A BROAD REGION OF
ISENTROPIC ASCENT WHICH WILL OVERSPREAD LOWER MI OVERNIGHT. THE
WATER VAPOR SHOWS AN INFLUX OF PACIFIC MOISTURE HEADING INTO NRN
PLAINS...SUPPORTING MODEL SOUNDINGS WHICH SHOW GOOD MID LEVEL
MOISTURE ADVECTION AFTER 06Z. THE BETTER PUSH OF DEEP LAYER MOISTURE
PRIOR TO DAYBREAK TUES WILL OCCUR ACROSS THE SAGINAW VALLEY AND
THUMB AND WILL WARRANT THE RAISING OF POPS SIGNIFICANTLY. FARTHER
SOUTH WEAKER FORCING AND LACK OF LOW LEVEL MOISTENING PRIOR TO 12Z
WILL SUPPORT ONLY LOW CHANCE POPS OR A DRY FORECAST. MOISTENING OF A
DEEP ISOTHERMAL LAYER NEAR -15C AND STEEP MID LEVEL LAPSE RATES
ACROSS THE TRI CITIES AND THUMB WILL WARRANT THE MENTION OF MINOR
SNOW ACCUMS /AN INCH OR LESS/ PRIOR TO DAYBREAK.

LONG TERM...

DIFFUSE SHORTWAVE ENERGY IS EXPECTED TO SLIDE THROUGH NORTHERN
PORTIONS OF THE CWA ON TUESDAY. THE VORTICITY MAXIMUM IS NOT
SURPRISINGLY WEAK WITH ENERGY ENTERING A REGION DOMINATED BY
CONFLUENT FLOW. WHAT THIS SYSTEM WILL HAVE GOING FOR IT DURING THE
MORNING HOURS IS SOME WARM AIR ADVECTION. THIS WAA IS SEEMINGLY
POTENT ENOUGH TO CARVE OUT THE SURFACE REFLECTION IN WHAT OTHERWISE
SHOULD BE A LARGE AREA OF HIGH PRESSURE. 295K SYSTEM RELATIVE
ISENTROPIC ASCENT WILL PASS THROUGH THE TRI CITIES...AT 12Z THEN
STRIPING THROUGH THE THUMB UNTIL 18Z. OVERALL CONFIDENCE IS HIGH
THAT A LOW QPF EVENT WILL VERIFY AND BOOSTED POPS INTO CATEGORICALS.
REALLY LIKE THE THERMODYNAMIC PROFILE FOR WHAT COULD BE SOME HIGHER
SNOW RATIOS. IT APPEARS THAT OVERACHIEVEMENT WOULD BE AT 1 INCH OF
SNOWFALL. BEST POTENTIAL FOR THIS WOULD BE THE THUMB. HIGH
TEMPERATURES ARE EXPECTED TO SETTLE RIGHT AROUND 20 DEGREES...15 TO
20 DEGREES BELOW AVERAGE.

A WEAK JETLET IS EXPECTED TO PUSH DIRECTLY EASTWARD FROM THE
SODAK/NE BORDER THROUGH SOUTHERN WISCONSIN TUESDAY NIGHT. THE
AGEOSTROPHIC RESPONSE OF THIS JETLET WILL BE TO INCREASE MIDLEVEL
FRONTOGENESIS. THERE IS MODEL VARIABILITY WITH REGARDS TO OVERALL
PRECIPITATION POTENTIAL FOR WEDNESDAY WITH SOME SOLUTIONS SUGGESTING
BEST THERMAL SUPPORT WILL PASS WELL SOUTH OF THE LOWER MICHIGAN.
FORECASTER PREFERENCE IS TO SIDE WITH THE ECMWF SINCE THE JETLET
SHOULD FAVOR A TRAJECTORY DIRECTLY INTO SOUTHEASTERN MICHIGAN
BECAUSE OF THE COMPACT/BUT SOMEWHAT SHEARED SHORTWAVE ENCROACHING
FAR NORTHERN LAKE SUPERIOR. THIS SHORTWAVE SHOULD HAVE SOME DRAWING
POWER TO THE JETLET. INCREASED POPS INTO THE MID CHANCE CATEGORY FOR
WEDNESDAY MORNING. ATTM...ACCUMULATION POTENTIAL IS INSIGNIFICANT
AND WILL WAIT UNTIL AFTER THE MORNING RUSH. CLOUDS AND SOME WARM AIR
ADVECTION SHOULD ALLOW TEMPERATURES TO RISE INTO THE MIDDLE 20S
WEDNESDAY.

IN THE WAKE OF THE LAKE SUPERIOR SHORTWAVE FOLDING THEN
AMPLIFYING...SOUTHEASTERN MICHIGAN WILL FEEL A QUICK SHOT OF COLD
AIR ADVECTION FOR THURSDAY. NOT EXPECTING TEMPERATURES TO LOWER ALL
THAT MUCH...BUT SHOULD BE ENOUGH TO HOLD ANY AIR MASS MODIFICATION
AT BAY.

MARINE...

SURFACE HIGH PRESSURE WILL BUILD ACROSS LOWER MICHIGAN AND LAKE
HURON THIS AFTERNOON. SURFACE WINDS ARE THEN EXPECTED TO INCREASE
MODESTLY OUT OF THE SOUTHWEST MONDAY NIGHT AND TUESDAY MORNING AHEAD
OF A WEAK CLIPPER SYSTEM. THE MAGNITUDE OF THE WINDS WILL REMAIN
MUTED GIVEN A VERY COLD ICE COVERED LAKES REGION. SURFACE WINDS WILL
THEN REMAIN UNORGANIZED OVER THE REGION FOR MUCH OF THE WEEK AS THE
AREA WILL BE IMPACTED WITHIN THE BACKDROP OF A LARGE AREA OF HIGH
PRESSURE. THIS HIGH WILL CERTAINLY BE DISRUPTED AT TIMES AS WEAK
AREAS OF LOW PRESSURE SWING THROUGH...ALTHOUGH ATMOSPHERIC STABILITY
WILL BE HIGH ENOUGH THAT IT WILL SEVERELY LIMIT THE SUCCESS OF THE
SURFACE REFLECTIONS.

&&

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

&&

$$

AVIATION.....SC
SHORT TERM...SC
LONG TERM....CB
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).