711
FXUS63 KDMX 010029
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
729 PM CDT WED SEP 30 2020
SHORT TERM
/TONIGHT THROUGH THURSDAY NIGHT/
ISSUED AT 313 PM CDT WED SEP 30 2020
CONFIDENCE: MEDIUM
MAIN FORECAST CONCERN WILL BE WIND INTO THE EARLY EVENING, THEN
TEMPERATURES AND FROST POTENTIAL FOR THURSDAY NIGHT. LOW OVER
MICHIGAN CONTINUES TO FORCE ADDITIONAL BOUNDARIES SOUTH THROUGH THE
REGION. OVERNIGHT BOUNDARY A BIT MORE ACTIVE WITH EARLY SHOWERS THAT
HAVE MOVED EAST. A SECONDARY BOUNDARY IS ENTERING SOUTHERN MN AT
1745Z AND WILL MOVE SOUTH TONIGHT INTO THURSDAY. THIS WILL ALSO
BRING SOME ADDITIONAL SHOWERS TO THE NORTH THIS EVENING AND TO
NORTHEAST IOWA AFTER 12Z THURSDAY THROUGH THE MORNING HOURS.
CYCLONIC FLOW ALOFT WILL SETTLE INTO THE REGION TOMORROW AND AGAIN
IN THE AFTERNOON THERE IS A SMALL RISK OF SOME SHOWERS MAINLY EAST
OF I35. HAVE INCLUDED AN AREA OF SLIGHT CHANCE IN THE FORECAST NOW,
AND THE OVERNIGHT SHIFT WILL NEED TO EVALUATE THE COVERAGE FOR
POSSIBLE EXTENSION WESTWARD. TONIGHT OVERNIGHT LOWS WILL DROP TO
THE LOWER TO MID 40S WITH AFTERNOON HIGHS THURSDAY CAPPED TO THE
LOWER 50S NORTH AND IN THE MID TO UPPER 50S OVER THE CENTRAL AND
SOUTH. SOME QUESTIONS REMAIN FOR THURSDAY NIGHT INTO FRIDAY WITH
REGARD TO CLOUDS AND TEMPS. THERE REMAINS A SPLIT IN GUIDANCE AS TO
THE ARRIVAL TIME OF THE CLOUDS FRIDAY. THE EURO AND SOME OF THE
HIRES GUIDANCE SUGGEST AN EARLIER ARRIVAL, SIMILAR TO YESTERDAY AFT
06Z TO 12Z WHILE THE GFS KEEPS THE THICKER CLOUDS TO OUR WEST AND
GENERALLY CLEAR THROUGH 12Z. OVERNIGHT MINS HAVE BEEN ADJUSTED A
COUPLE OF DEGREES UPWARD THIS PACKAGE, DUE TO INCREASE IN CLOUDS AND
GUIDANCE WHICH IS ALSO WARMER. LOWS THURSDAY NIGHT WILL FALL TO
AROUND 32 IN THE NORTHWEST TO THE UPPER 30S SOUTH. THIS WILL STILL
GIVE WAY TO FROST OVER A GOOD SHARE OF THE FORECAST AREA, THOUGH A
HARD FREEZE IS NOT ANTICIPATED AT THIS TIME.
LONG TERM
/FRIDAY THROUGH WEDNESDAY/
ISSUED AT 313 PM CDT WED SEP 30 2020
CONFIDENCE: MEDIUM
FRIDAY TEMPERATURES WILL RECOVER THE TO THE 50S WITH CLOUDS
CONTINUING ACROSS THE REGION. HIGHS WILL REACH THE LOWER 50S
NORTHEAST TO THE MID TO UPPER 50S SOUTHWEST. THE NEXT SYSTEM WILL BE
ARRIVING FRIDAY NIGHT WITH SHOWERS SPREADING OVER THE REGION. THERE
IS PRETTY HIGH CONFIDENCE IN THE COVERAGE AND TIMING OF
PRECIPITATION WHICH SHOULD CONTINUE THROUGH SATURDAY NIGHT. THOUGH
RAINFALL AMOUNTS ARE EXPECTED TO BE UNDER A HALF INCH FOR THE EVENT,
LIGHT SHOWERS WILL BE AROUND FOR ABOUT 24 TO 36 HOURS. TODAY THE
GFS IS SHOWING A WEAKER SOLUTION WHILE THE EURO IS SLIGHTLY MORE
DEVELOPED WITH THE LOW CROSSING JUST SOUTH OF THE STATE. LOWS OVER
THE WEEKEND MAY NEED A SLIGHT ADJUSTMENT IF CLOUD COVERAGE REMAINS
THICK ENOUGH. CURRENTLY THE MID 30S OVER THE NORTH MAY BE TOO LOW
FOR SATURDAY AND SUNDAY MORNING. ONCE THE SYSTEM TRACKS EAST OF THE
REGION BY MIDDAY SUNDAY, CLOUDS WILL BE ON THE DECREASE THROUGH
SUNSET. MONDAY MORNING MAY BE ANOTHER PERIOD OF POTENTIAL FROST AS A
RIDGE OF HIGH PRESSURE BUILDS INTO IOWA. A QUICK TRANSITION TO A
SOUTHWEST FLOW BY AFTERNOON WITH DECENT MIXING WILL BRING WARM AND
BREEZY CONDITIONS BACK TO THE AREA WITH AFTERNOON HIGHS WELL INTO
THE 60S. THE WARMING TREND WILL CONTINUE INTO WEDNESDAY AS HIGHS ARE
MAINTAINED IN THE 70S BOTH DAYS. OVERNIGHT MINS WILL MODERATE TO
THE 40S TO AROUND 50 WITH NO PRECIPITATION EXPECTED DURING THE
PERIOD.
AVIATION
/FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING/
ISSUED AT 725 PM CDT WED SEP 30 2020
VFR CONDITIONS WITH LIGHTER WINDS EXPECTED THIS EVENING AND
OVERNIGHT. NORTHERN SITES (KMCW AND KALO) WILL LIKELY DROP INTO
MVFR CEILINGS WITH ANOTHER BOUNDARY APPROACHING THURSDAY MORNING
THAT COULD ALSO BRING SOME VCSH TO BOTH SITES THROUGH MIDDAY.
INCREASED MIXING AFTER SUNRISE WILL INCREASE WINDS AT ALL SITES
FOR MOST OF THURSDAY WITH NW WINDS GUSTING TO NEAR 25 KTS.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...REV
LONG TERM...REV
AVIATION...KCM
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