FXUS63 KDMX 282336
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
534 PM CST SAT NOV 28 2009
.SHORT TERM /TONIGHT/...
SURFACE COLD FRONT CURRENTLY FROM NEAR MILWAUKEE TO CLARINDA
WILL CONTINUE SLOWLY MOVING SOUTHEAST THIS EVENING...BUT WILL GET A
KICK IN THE REAR FROM THE UPPER LEVEL TROUGH DROPPING THROUGH ND AND
EVENTUALLY OVER IOWA LATER TONIGHT. HIGHER PRESSURE WILL BUILD IN
MORE ASSERTIVELY AFTER MIDNIGHT...SO WILL HAVE NNWLY WINDS PICKING
UP AND GUSTING UP TO 25 MPH OR SO. A DECENT SLUG OF QG FORCING
SLIDES OVER THE STATE TONIGHT...BUT DEEPER MOISTURE IS LACKING.
FORCING AND SUFFICIENT MOISTURE FOR PRECIP SHOULD STAY NORTH OF OUR
AREA. HAVE INCREASED POPS AFTER MIDNIGHT ACROSS THE NORTH TO ACCOUNT
FOR PROXIMITY TO EXPECTED PRECIP GENERATION ZONE...BUT HAVE LEFT
THEM BELOW MENTIONABLE LEVELS...THOUGH AN ERRANT SNOWFLAKE OR TWO
CANNOT BE RULED OUT. THE ONLY OTHER NUANCE TO TONIGHTS FORECAST IS
REGARDING THE INCREASE IN LOW LEVEL MOISTURE BEING WEAKLY LIFTED BY
UPPER LEVEL WAVE THAT SHOULD RESULT IN STRATUS DEVELOPING AND MOVING
SOUTH LATE. AND IN THE NEAR TERM...THERE IS A SMALL PATCH OF STRATUS
ACROSS SW MN MOVING SOUTHEAST. AM HOPING IT WILL MIX OUT AS IT
APPROACHES NW IA...BUT WITH DECOUPLING TIME APPROACHING FAST THIS
TIME OF YEAR...MAY HAVE TO INCLUDE THESE CLOUDS IN THE EARLY EVENING
PORTION OF THE FORECAST FOR NRN SECTIONS.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
TEMPS WILL BE THE PRIMARY CONCERN
THROUGH TUESDAY WITH A SUITABLY DRY ATMOSPHERIC COLUMN AND NO PRECIP
EXPECTED. MID/UPPER WAVE WILL PUSH ACROSS IOWA BEHIND THE COLD FRONT
ON SUNDAY AFTERNOON/EVENING....THEREAFTER EXPECT RIDGING THROUGH
TUESDAY WITH A STEADY WARMING TREND DURING THE EARLY PART OF THE
WEEK. WEAK SURFACE TROUGH MAY GLANCE OUR NORTHEASTERN COUNTIES ON
MONDAY...PROVIDING CHANCES FOR HIGHER CLOUD COVER AND SOMEWHAT
COOLER TEMPERATURES IN THAT AREA.
ANOTHER COLD FRONT WILL TRAVERSE THE STATE ON TUESDAY NIGHT WITH A
LARGE MID/UPPER LOW MOVING INTO THE WESTERN GREAT LAKES REGION FROM
LATE WEDNESDAY INTO FRIDAY. THE LOW CLOUD SHIELD AROUND THIS LOW
WILL EXTEND ACROSS MOST OR ALL OF OUR AREA DURING THIS TIME...WITH
SUBTLE SHORTWAVES MOVING AROUND THE GYRE ENHANCING THE POSSIBILITY
OF LIGHT SNOW AT TIMES MAINLY IN OUR NORTH AND NORTHEAST. FORECAST
SOUNDINGS INDICATE THAT MOISTURE WILL BE VERY LIMITED SO HAVE ONLY
MENTIONED A CHANCE OF FLURRIES ON THURSDAY FOR NOW. IN GENERAL
WEDNESDAY NIGHT AND THURSDAY WILL BE COLD AND BLUSTERY...AND HAVE
LOWERED MAX TEMPS ON THURSDAY TO ACCOUNT FOR THICK CLOUD COVER AND
STRONG CAA.
TOWARD THE END OF THE WEEK LONG RANGE MODELS DIVERGE WITH THE ECMWF
AND GEM MAINTAINING CYCLONIC FLOW ACROSS OUR AREA AROUND THE LARGE
LOW TO THE EAST...WHILE THE GFS MOVES THAT LOW OUT AND ATTEMPTS TO
DIG A BROAD BASED TROUGH INTO THE WEST. GIVEN THAT THE FORMER
SOLUTION HAS BEEN MORE CONSISTENT...MADE LITTLE CHANCE TO THE
EXTENDED FORECAST WHICH REFLECTS THAT SCENARIO.
&&
.AVIATION...
29/00Z...WX PROB OF THE TAF PD IS WITH THE IFR AND MVFR CONDS POST
FRONTAL. AREA OF LOW ST AND BR OVR SWRN MN IS LKLY TO EXPAND SWD
OVR NGT. WNDS WILL INC FM THE N AND EXPECT TO SEE MVFR BR CONDS OVR
THE NRN 3 TAF SITES WITH MVR TO OCNLY IFR CIGS IN THESE AREAS. SRN
SITES XPCTD TO REMAIN VFR FOR THE MOST PART WITH A 6 HR PD OF MVFR
CIGS LATE TNGT INTO SUN MRNG. CONDS IPVG IN THE N DURG THE DAY
SUN...HWVR MVFR CIGS LKLY TO HOLD THRU MUCH OF THE AFTN IN KMCW AND
KALO.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MOYER
AVIATION...MS NOV 09
LONG TERM...LEE