FXUS63 KDVN 142004
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 PM CDT SUN MAR 14 2010
.SYNOPSIS...
CLEARING SKIES UNDERWAY ACROSS THE UPPER MIDWEST AS SURFACE HIGH
PRESSURE MOVES IN. UPPER AIR ANALYSIS SHOWS SUBSIDENCE TO DOMINATE
WITH UPPER RIDGING FOR FAIR SKIES AND MILDER TEMPS NEXT SEVERAL DAYS.
CURRENT TRENDS WITH MID MARCH SUNSHINE SUPPORTS HIGHS SLIGHTLY ABOVE
GUIDANCE FOR MAX TEMPS AND MINS JUST BELOW GUIDANCE WITH DECOUPLING
OF WINDS.
&&
.SHORT TERM...TONIGHT AND SUNDAY...
TONIGHT...FAIR TO MOSTLY FAIR SKIES WITH MOST SOLUTIONS OVERDOING BL
MOISTURE AND UNDERPLAYING SUBSIDENCE AND MOISTURE DIVERGENCE. SOME
CLOUDS FROM OFF LAKE MICHIGAN POSSIBLE TONIGHT FOR LATER SHIFTS TO
MONITOR. HAVE MINS IN MID TO UPPER 30S BUT AREAS OF FROST POSSIBLE
TOWARD DAYBREAK AND LOCALLY LOWER MINIMUMS WITH COOL AIR POOLING ON
NEARLY CALM TO LIGHT NORTH WINDS.
MONDAY...NICE EARLY SPRING DAY WITH LOTS OF SUNSHINE. GOOD BL MIXING
TO ALLOW FOR NORTH WINDS TO REACH 10-15 MPH BY AFTERNOON. LOCAL TOOLS
AND PERSISTENCE SUPPORT MAX TEMPS OF 55-60 DEGREES...WARMEST TEMPS
MOST LOCATIONS SINCE LAST NOVEMBER. ..NICHOLS..
.LONG TERM...
MONDAY NIGHT THROUGH TUESDAY NIGHT...SFC RIDGE AXIS WILL EDGE DOWN
ACRS THE NORTHERN PLAINS MON NIGHT. WITH SOME CLEARING LOCALLY...
EXPECT WIDESPREAD LOWS IN THE MID TO UPPER 30S MON NIGHT INTO TUE
MORNING. DEPENDING ON DRY MIXING IN THE BOUNDARY LAYER DURING THE
DAY ON MON...SFC WIND DECOUPLE MON NIGHT MAY FOSTER SOME PATCHY FOG
DEVELOPMENT BY TUE MORNING BUT WILL HOLD OFF MENTION FOR NOW. THE
RIDGE RIDING UPPER WAVE STILL SLATED TO PROPAGATE DOWN SOUTHWARD
ACRS THE UPPER MID WEST LATER TUE AND TUE NIGHT. THE CANADIAN GEM AND
NEW 12Z ECMWF HAVE TRENDED FURTHER WESTWARD WITH THEIR SUPPORT IN
PRODUCING SCTRD SHOWERS AND SPRINKLES WITH THEIR SOLUTIONS
SUGGESTING THE BULK OF THE ACTIVITY TO REMAIN WEST OF THE DVN CWA.
WITH ONGOING CHC POPS ALREADY IN PLACE AND THE 12Z GFS STILL
SUGGESTING A DIRECT HIT WITH SHOWERS LATE TUE AND TUE NIGHT ON THE
LOCAL AREA...WILL LET THE POPS RIDE AND WILL ADD SLIGHT CHC TO THE
NORTHWEST FOR TUE AFTERNOON. EVEN IF THE SHOWERS AND SPRINKLES SWEEP
RIGHT ACRS THE CWA LATE TUE AND TUE NIGHT...THEY WILL PRODUCE
MINIMAL HIT AND MISS RAINFALL AMOUNTS OF GENERALLY UNDER A TENTH OF
AN INCH AND WILL NOT BE MUCH OF A FACTOR TO THE ONGOING HYDRO
SITUATION.
IN THE EXTENDED/WEDNESDAY THOUGH NEXT SUNDAY/...
WED...WILL WALK OUT LINGERING LIGHT SHOWERS OUT OF THE SOUTH IN THE
MORNING...WITH AFTERNOON BREAKS IN THE CLOUD COVER AND MIXING HELPING
TEMPS WARM BACK UP INTO AT LEAST THE MID 50S. TEMPS TO DIP INTO THE
LOWER 40S TO UPPER 30S WED NIGHT BEFORE LLVL RETURN FLOW COMMENCES.
THU...RETURN FLOW INCREASES AND MODERATING THERMAL PROFILES MIX OUT
TO HIGHS IN THE UPPER 50S TO LOWER 60S IN THE BULK OF THE DVN FCST
AREA...MAYBE HELD IN THE LOW TO MID 50S IN THE FAR NORTH.
FRI THROUGH SUNDAY...MAINLY ASSESSING THE NEW 12Z MEDIUM RANGE MODEL
RUNS THIS PERIOD FOR THEIR HANDLING OF THE L/W PHASING PROCESS AND
POTENTIAL WEEKEND STORM SYSTEM. THE NEWLY ARRIVED 12Z ECMWF HAS
TRENDED BACK TOWARD THE 12Z AND EARLIER RUN GFS IN BECOMING MORE
PHASED WITH THE SYNOPTIC SCALE FEATURE JUST UPSTREAM ACRS THE
PLAINS BY LATE FRI...ALLOWING FOR A STRONGER SFC SYSTEM AND LOW
DEVELOPMENT WHICH COULD IMPACT THE DVN FCST AREA FROM LATE FRIDAY
THROUGH SAT. A MORE PHASED AN SLOWER SYSTEM ALLOWS FOR MORE PRE-
FRONTAL WARMING ON FRI WITH HIGHS IN THE UPPER 50S INTO THE 60S
POSSIBLE BEFORE CLOUDS AND PRECIP INCREASE FROM THE WEST BY LATE
AFTERNOON. WIDESPREAD POST FRONTAL RAINS FRI NIGHT MAY TOTAL UP CLOSE
TO AN INCH BY SAT MORNING...WITH LLVL COLD CONVEYOR CAUSING A
SWITCH OVER TO SNOW IN THE FAR WEST AND NORTHWEST AFTER MIDNIGHT.
THE GFS IS MORE BULLISH WITH A DEEPER SOUTH PHASING IN THE SOUTHERN
PLAINS AND SUBSEQUENT DEVELOPMENT OF A STRONGER/CUT-OFF UPPER LOW
OVER THE SOUTHEAST PLANS BY SAT MORNING. THE GFS/S ASSOCIATED SFC
SYSTEM THEN TAKES THE CLASSIC PATH TO PRODUCE WET ACCUMULATING MARCH
DEF ZONE SNOWS IN MUCH OF THE DVN CWA LATE SAT AND SAT NIGHT.
ALTHOUGH THE EURO HAS A SWITCH OVER AS WELL TO SNOW LATE FRI NIGHT
AND SAT...IT IS SLOWER IN DEVELOPMENT WITH RESPECT TO FRONTAL LOW
PRESSURE IN IT/S SOUTHERN STREAM IN A WAY TO AFFECT THE LOCAL AREA
WITH HEAVY WET SNOW AND IS MORE PROGRESSIVE WITH PRECIP EXITING THE
CWA BY SAT EVENING. STILL NEED MORE RUNS OVER THE NEXT 24-36 HOURS
FRO MORE CONFIDENCE AND TO IRON OUT PHASING ISSUES...BUT WILL
MAINTAIN A RAIN OR SNOW MIX WORDING FOR LATE FRI NIGHT INTO SAT.
COLD NORTHWEST FLOW TO MAKE FOR BELOW NORMAL CONDITIONS TEMP-WISE FOR
SUNDAY INTO EARLY NEXT WEEK. ..12..
&&
.AVIATION...
FAIR SKIES TO PREVAIL BY SUNSET WITH VFR CONDITIONS ALL TERMINALS AND
VSBYS AOA 7 MILES. LIGHT NORTH WINDS OF 5-10 MPH INTO LATE MONDAY
MORNING. ISOLATED PATCHY GROUND FOG POSSIBLE WITHIN A COUPLE OF
HOURS OF SUNRISE. MONDAY...FAIR SKIES WITH CUMULUS CLOUDS DEVELOPING
MID DAY WITH BASES AOA 3K AGL. ..NICHOLS..
&&
.HYDROLOGY...
MOST RIVERS REMAIN IN MINOR TO MODERATE FLOOD...TRIBUTARIES CRESTING
OR SCHEDULED TO CREST NEXT 2-3 DAYS. MISSISSIPPI RIVER TO RISE TO
MINOR FLOOD STAGE SOUTH OF QUAD CITIES LATE THIS WEEK. ..NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS/12
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