FXUS63 KDTX 111101 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 601 AM EST THU MAR 11 2010 .AVIATION... FOG/STRATUS HAS HAD TROUBLE EXPANDING OVERNIGHT...BUT STILL HAVE TO WATCH DTW AS AREA OF IFR/LIFR STRATUS HAS FORMED OFF TO THE SOUTH OR SOUTHWEST AND MAY BUILD INTO THE AREA BEFORE ERODING EARLY IN THE FORECAST. OTHERWISE...EXPECT ANY AREA OF BR WITH MVFR VSBYS TO LIFT THIS MORNING...WITH VFR CONDITIONS INTO THE EVENING. MVFR/IFR CIGS AND/OR VSBYS WILL THEN GRADUALLY EXPAND NORTH THROUGH THE AREA AFTER 02Z OR SO AS THE FIRST SIGNIFICANT PUSH OF MOISTURE LIFTS INTO THE REGION AS LOW PRESSURE SPINS UP OVER IOWA. && .PREV DISCUSSION...ISSUED 417 AM EST THU MAR 11 2010 SHORT TERM...TODAY MOISTURE WILL INCREASE THROUGHOUT THE DAY AS A STRONG LOW PRESSURE SYSTEM LIFTS INTO IOWA. HOWEVER...AS THIS LOW BASICALLY STALLS OVER THE MID MISSOURI VALLEY OVER THE NEXT DAY OR TWO...THE MAIN PUSH OF MOISTURE WILL BE NORTHWARD...AND ANY SIGNIFICANT RAIN WILL FOR THE REGION WILL LIKELY HOLD OFF UNTIL LATE IN THE DAY...AND MORE LIKELY LATER THIS EVENING...FOR MOST LOCATIONS. SO...WILL MAINTAIN A DRY FORECAST THROUGH 21Z FOR THE FAR SOUTHERN PORTION OF THE CWA AND KEEP ALL OTHER AREAS DRY THROUGH 00Z. WITH A RATHER THIN VEIL OF CLOUDS DURING THE FIRST HALF OF THE DAY...THE TEMPERATURES WILL BE ABLE TO CLIMB RATHER STEADILY. AGAIN...PRETTY MUCH ALL LOCATIONS...ASIDE FROM THE IMMEDIATE GREAT LAKE SHORELINE AREAS...WILL CLIMB WELL INTO THE 50S...WITH LOWER 60S QUITE POSSIBLE AS WELL AS PLENTY OF SUNSHINE FILTERS THROUGH THE STEADILY INCREASING CIRRUS DECK. LONG TERM...TONIGHT THROUGH NEXT WEDNESDAY THE PLUME OF MOISTURE RESPONSIBLE FOR THE NOCTURNAL THUNDERSTORM ACTIVITY ACROSS THE MID-MISSISSIPPI VALLEY WILL REACH LOWER MICHIGAN OVERNIGHT. SHORTWAVE ENERGY SEEN ON WATER VAPOR ACROSS ARKANSAS AND MISSISSIPPI WILL ROTATE NORTH AROUND THE EASTERN PERIPHERY OF THE UPPER LOW TOWARDS WISCONSIN. THE APPROACHING RIBBON OF MOISTURE IS CERTAINLY EXPECTED TO LOSE SOME OF ITS ENERGY AS IT APPROACHES SOUTHEAST MICHIGAN...MOVING INTO AN AREA OF ONLY WEAK ELEVATED INSTABILITY. THE STRONGER FORCING AND MID-LEVEL HEIGHT FALLS WILL PASS TO OUR WEST FROM CHICAGO NORTH ACROSS LAKE MICHIGAN. DESPITE BEING A LITTLE FURTHER REMOVED FROM THE BETTER DYNAMICS...850MB DEWPOINTS CLIMB AS HIGH AS 7C WITH PW VALUES AROUND AN INCH. THE COMBINATION OF MOISTURE ADVECTION AND LIFT REMAINS HIGH ENOUGH TO EXPECT WIDESPREAD RAIN WITH A FEW THUNDERSTORMS POSSIBLE...AND QPF OF .20-.50 INCH. THERE REMAINS NO THREAT OF SEVERE WEATHER WITH ANY THUNDERSTORM ACTIVITY ACROSS SOUTHEAST MICHIGAN TONIGHT. LOWS TONIGHT WILL REMAIN MILD RANGING FROM NEAR 40 THUMB...TO NEAR 50 SOUTH. MEANWHILE SHORTWAVE ENERGY NEAR THE FOUR CORNERS REGION WILL RACE ACROSS THE SOUTHERN PLAINS...LIFTING NORTH UP THE MID-MISSISSIPPI VALLEY AS IT GETS ABSORBED INTO THE PLAINS UPPER LOW. SURFACE PRESSURE FALLS LIFT FROM THE TENNESSEE TO OHIO VALLEY AHEAD OF THIS FEATURE...ENHANCING THETA-E ADVECTION FROM NORTHERN OHIO INTO SOUTHEAST MICHIGAN AS THE PRESSURE GRADIENT TIGHTENS ON THE NORTHERN FLANK OF THE SYSTEM. SCATTERED SHOWERS WILL DEVELOP DURING THE AFTERNOON ON FRIDAY AND INCREASE IN COVERAGE OVERNIGHT AS THIS SYSTEM STARTS TO PROGRESS EASTWARD. OVER THE COURSE OF THE WEEKEND THIS SLOW MOVING BUT EXPANSIVE SYSTEM WILL SHIFT FROM THE MID-MISSISSIPPI VALLEY TO THE EAST COAST. CYCLONIC FLOW OFF THE ATLANTIC OCEAN CONTINUES TO FUNNEL MOIST AIR FROM THE MID-ATLANTIC TO THE CENTRAL GREAT LAKES. RAIN IS EXPECTED TO CONTINUE FROM FRIDAY NIGHT THROUGH THROUGH AT LEAST SATURDAY NIGHT WITH VARIOUS SHORTWAVES CAUSING ENHANCEMENT. WE WILL BE KEEPING AN EYE ON AREA RIVERS THROUGH THE WEEKEND GIVEN THE RECENT SNOW MELT...FROZEN SOILS...AND QPF POSSIBLY EXCEEDING 1.50 INCHES BY SUNDAY. TEMPERATURES WILL BEGIN TO DROP BY SATURDAY...GENERALLY INTO THE 40S (POSSIBLY HOLDING NEAR 50 IN THE SOUTH) AS WINDS INCREASE AND BACK GIVING THEM A SLIGHT NORTHEASTERLY COMPONENT. THE NORTHEASTERLY FLOW INCREASES ON SUNDAY AS THE LOW PRESSURE SYSTEM PULLS AWAY OFF THE EAST COAST. THE SPLIT FLOW WITH RIDGING OVER CANADA MEANS THAT THERE IS NOT A LOT OF COLD AIR TO BE ADVECTED OVER THE AREA UNDER THE NORTHERLY FLOW...MEANING TEMPERATURES WILL STAY AT OR ABOVE NORMAL INTO NEXT WEEK. SUN RETURNS BY MONDAY AND TUESDAY WITH DRIER AIR CONTRIBUTING TO A LARGE DIURNAL SWING AND HIGHS CREEPING BACK UP TOWARDS THE 50 DEGREE MARK BY TUESDAY/WEDNESDAY. MARINE... EASTERLY WINDS WILL GRADUALLY INCREASE HEADING INTO THE WEEKEND AS A LOW PRESSURE SYSTEM...CURRENTLY LIFTING INTO IOWA...TRACKS EAST INTO THE OHIO VALLEY BY THE WEEKEND. GIVEN THE FACT THAT RELATIVELY MILD AIR WILL BE FLOWING OVER COLD LAKE WATERS...THERE WILL BE A NOTABLE STABLE LAYER ABOVE THE WATER...WHICH WILL PREVENT GALE FORCE WINDS FROM MIXING DOWN TO THE SURFACE. HOWEVER...SMALL CRAFT ADVISORIES MAY BE NEEDED ALONG THE NEARSHORE WATERS OF LAKE HURON AS WINDS GUST BETWEEN 20 TO 25 KNOTS BY LATE SATURDAY INTO SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....DG SHORT TERM...DG LONG TERM....KEC MARINE.......DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).