National Weather Service Weather Forecast Office

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

000
FXUS63 KDTX 130735
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
335 AM EDT MON MAY 13 2013

.SHORT TERM... TODAY AND TONIGHT

WESTERN EXTENSION OF THE EXPANSIVE LONGWAVE TROUGH EMANATING FROM
THE DEEP CLOSED LOW CIRCULATING THROUGH QUEBEC WILL SLOWLY EXIT THE
CENTRAL GREAT LAKES REGION TODAY.  THE RESIDENT COLD MID MAY
CONTINENTAL POLAR AIRMASS WILL SEE THE INITIAL STAGES OF A
PROGRESSIVE MODERATING TREND IN THE WAKE OF THE EXITING THERMAL
TROUGH...AS A GENERAL RECOVERY IN THE UPPER HEIGHT FIELD LENDS
ROUGHLY 5-7 DEGREES OF ADDITIVE WARMTH INTO THE 850-925 MB LAYER.
THIS COMBINED WITH A HIGH DEGREE OF INSOLATION WILL BRING DAYTIME
TEMPERATURES INTO THE LOWER AND MIDDLE 50S THIS AFTERNOON...STILL A
GOOD 10-12 DEGREES BELOW NORMAL.  EXPANDING LOW LEVEL ANTICYCLONIC
FLOW WILL PROVIDE A CONSIDERABLY WEAKER WESTERLY GRADIENT FLOW FOR
TODAY.

SURFACE RIDGE AXIS WORKS THROUGH DURING THE EARLY PART OF THE
NIGHT.  GIVEN THE WEAK GRADIENT...A PERIOD OF CLEAR SKY AND DRY MID
LEVEL CONDITIONS...LOOKING AT A WINDOW OF FAVORABLE RADIATIONAL
COOLING BEFORE A LIGHT SOUTH FLOW KICKS IN AND THICKER HIGH CLOUDS
SPILL EAST LATE.  THIS WILL SUPPORT LOWS PREDOMINATELY WITHIN THE
MID-UPPER 30S RANGE.  THIS WILL INTRODUCE AT LEAST A LOW PROBABILITY
FOR SOME PATCHY FROST FORMATION ACROSS THE THUMB REGION...ALTHOUGH
THE INBOUND CLOUD COVER AND EMERGING SOUTHERLY GRADIENT MAY PROVE TO
BE A HINDERANCE.  THIN CORRIDOR OF MID LEVEL FORCING TIED TO AN
EXPANDING WING OF WARM AIR ADVECTION/ISENTROPIC ASCENT WILL BE AT
THE DOORSTEP OF THE SAGINAW VALLEY BY DAYBREAK.  THIS MAY TRANSLATE
INTO A FEW LIGHT SHOWERS/SPRINKLES WORKING INTO THAT REGION PRIOR TO
12Z...WORTHY OF A SMALL POP MENTION.

&&

.LONG TERM...

THE RECORD/NEAR RECORD COLD THIS MORNING WILL BE A DISTANT MEMORY BY
THE TIME WEDNESDAY ROLLS AROUND. UPPER LEVEL RIDGE OVER THE ROCKIES
THIS MORNING...WITH WARM AIR EXTENDING INTO SOUTHERN
SASKATCHEWAN/ALBERTA...WHERE HIGHS REACHED INTO THE 80S YESTERDAY.
THIS AIRMASS WILL BE REACHING US TUESDAY NIGHT...WHICH MAKES FOR A
DIFFICULT WEDNESDAY FORECAST AS POSSIBLE CONVECTION WITH WELL
DEFINED SURFACE TROUGH/COLD FRONT A POSSIBLE BIG HINDRANCE AT THIS
POINT...ALONG WITH LOW LEVEL COLD ADVECTION DURING THE DAY. THE
FORECAST FOR TUESDAY IS NOT MUCH EASIER...AS WARM FRONT DOES NOT
LOOKING TO BE LIFTING THROUGH BY 00Z WEDNESDAY...WHICH WILL
OBVIOUSLY PREVENT TEMPS FROM SOARING ON TUESDAY...AS STRONG
SOUTHEAST FLOW AND CLOUDS HOLD MAX TEMPS IN THE 60S (PROBABLY LOWER
60S)...ESPECIALLY IF SOME RAIN SHOWERS CAN DEVELOP WITH THE 850-700
MB MOISTURE SURGE.

IMPRESSIVE AMOUNT OF WARM AIR TO ARRIVE TUESDAY NIGHT...AS 1000-500
MB THICKNESS OF 570 DAM ENCOMPASS SOUTHEAST MICHIGAN AT 12Z
WEDNESDAY. 00Z GFS SHOWING SOME REAL STEEP MID LEVEL (700-500 MB)
LAPSE RATES (8-8.5 C/KM) ROLLING THROUGH TUESDAY NIGHT...SUPPORTING
A SOLID CHANCE OF SHOWERS AND THUNDERSTORMS. WEDNESDAY THE COLD
FRONT SINKS SOUTH OF THE BORDER EARLY IN THE DAY WITH SOME MODEST
HEIGHT FALLS OCCURRING. HOWEVER...THINKING TEMPERATURES WILL DO WELL
WITH THE FAVORABLE WESTERLY FLOW...AND EVEN WITH THE COLD ADVECTION
DROPPING 850 MB TEMPS INTO THE LOWER TEENS. STILL THINK WE WILL MAKE
IT INTO THE UPPER 70S TO LOWER 80S AS WE BEGIN TO DRY
OUT...PROMOTING MIXING DEPTHS TOWARD 800 MB. A QUICK LOOK AT THE 00Z
EURO SHOWS A SLOWER COLD FRONT PASSAGE...MAKING MID 80S A
POSSIBILITY FOR WEDNESDAY WITH 850 MB TEMPS IN THE MID TEENS.

00Z MEDIUM RANGE MODELS ALL IN PRETTY GOOD AGREEMENT THE FRONTAL
BOUNDARY WILL SINK SOUTH TOWARD THE OHIO RIVER...LEADING TO A DRY
THURSDAY OVER SOUTHEAST MICHIGAN. THERE IS A SLIGHT CHANCE WEDNESDAY
NIGHT A FEW MID LEVEL BASED SHOWERS COULD RIDE THE OHIO BORDER AS A
WEAK SHORTWAVE MAY TRACK THROUGH THE AREA. TRENDS FOR FRIDAY ALSO
SHOW HIGH PRESSURE HOLDING (MAINTAINING DRY WEATHER)...BUT THERE IS
ENOUGH OF A CONCERN WITH RETURN MOISTURE/WARM FRONT APPROACHING TO
CARRY LOW CHANCE POPS...WITH INCREASING CHANCE OF ACTIVITY AS WE
HEAD INTO THE WEEKEND AND EARLY NEXT WEEK AS LONGWAVE TROUGH
ADVANCES INTO THE CENTRAL CONUS.

&&

.MARINE...

LINGERING SMALL CRAFT CONDITIONS FOR ELEVATED WAVES WILL GRADUALLY
EASE THIS MORNING AS THE NORTHWEST GRADIENT SLACKENS.  HIGH PRESSURE
WILL SETTLE ACROSS THE REGION THROUGH TONIGHT PROVIDE GENERALLY
FAVORABLE MARINE CONDITIONS.  A STABLE 10 TO 15 KNOT SOUTHEAST FLOW
WILL DEVELOP ON TUESDAY IN ADVANCE OF A WARM FRONT.  THE PASSAGE OF
THE WARM FRONT WILL BRING A CHANCE OF THUNDERSTORMS TUESDAY NIGHT.
WINDS SHIFT TO WESTERLY AND TURN GUSTY WITH A COLD FRONTAL PASSAGE
ON WEDNESDAY.  THUNDERSTORMS WILL AGAIN BE POSSIBLE WITH THIS FRONT.

&&

.AVIATION...ISSUED 1149 PM EDT SUN MAY 12 2013

//DISCUSSION...

HIGH PRESSURE BUILDING INTO THE REGION WILL PROVIDE MOSTLY CLEAR
SKIES AND LIGHT WINDS THROUGH MONDAY MORNING. THE RIDGE ITSELF WILL
TRACK THROUGH THE CENTRAL GREAT LAKES ON MONDAY. WIND GUSTS WILL
PICK BACK UP TO 10 TO 15 KNOTS DURING THE DAY ON MONDAY WITH DAYTIME
HEATING ALONG WITH SOME DIURNAL CUMULUS CLOUDS. HOWEVER WITH WARMER
AIR BUILDING IN AND SUBSIDENCE ASSOCIATED WITH THE RIDGE COVERAGE IS
EXPECTED TO BE SCATTERED. A WEAK LOW PRESSURE SYSTEM TRACKING
THROUGH THE REGION MONDAY NIGHT WILL BRING THICKENING MID LEVEL
CLOUDS TO THE TAF SITES.

//DTW THRESHOLD THREATS...

* NONE.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...FREEZE WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060-
     MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-
     MIZ083...UNTIL 8 AM MONDAY.

LAKE HURON...
     SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
     HURON INCLUDING OUTER SAGINAW BAY...UNTIL 10 AM MONDAY.

LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

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


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