Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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298 FXUS63 KMPX 300807 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 307 AM CDT Mon Sep 30 2024 .KEY MESSAGES... - Critical fire weather conditions expected this afternoon in western and central MN as gusty winds and dry air will arrive following a cold front. A Red Flag Warning has been issued. - Cooler Tuesday with seasonable temperatures in the mid 60s. - Dry weather for the rest of the period with temperatures fluctuating from normal to above-normal. && .DISCUSSION... Issued at 305 AM CDT Mon Sep 30 2024 By late September standards, temperatures tonight have stayed rather balmy. Lows are mainly in the 50s but warmer air is present in western MN where lows have only reached the low 60s. Southeasterly winds in western MN have also remained steady with gusts reaching 20- 25 mph. Area winds are expected to increase throughout today, turning more southerly this morning, as a trough arrives from the west. Along the Buffalo Ridge, gusts this morning could reach 35 mph as a strong southwesterly LLJ quickly passes overhead. Temperatures will rise quickly into the low to mid 80s this afternoon before a strong cold passes through from west to east. As the front passes, winds will quickly rotate counter-clockwise to northwesterly and increase in speed. Sustained values across western MN will be between 17-23 mph this afternoon with gusts of 25 to in excess of 30 mph. As one goes east, wind strength should slowly decrease but gusts of 30 mph are still possible at MSP and eastern MN. Additionally, our already arid air will only dry out more following the front. Relative humidity values across western and southwestern MN will drop to 15-25% (lowest values in extreme western MN) by late this afternoon. RH values in the mid to upper 20s are expected for the rest of our MN counties while values improve to above 35% in WI. With these factors in mind (and our prolonged recent dry spell), have issued a Red Flag Warning for portions western and central MN from late this morning until this evening. Critical fire weather conditions will foster an environment for any sparks or flames to quickly grow out of control. For most of the rest our MN counties to the east, a Special Weather Statement has been issued for elevated fire weather conditions. Some uncertainty does exist on the duration and extent the strongest wind gusts will overlap with the driest air. The northwesterly winds will spread east tonight and remain pretty gusty through about 1 AM as cold air following the front will keep the boundary layer mixed. Wind gusts could still reach 25-35 mph around midnight. Eventually, the boundary layer will begin to collapse as we cool, suppressing the flow to the surface. Lows by Tuesday morning will be in the 40s. The northwesterly winds will still be breezy thru most of Tuesday with gusts near 20 mph. Highs are forecast to be much cooler in the low to mid 60s. The remainder of the period continues to look dry as guidance shows us lacking any southerly return flow moisture. Temperatures will fluctuate a bit, though, as waves within zonal flow move through the Northern Plains. Highs on Wednesday are forecast to reach the mid 70s to even lower 80s prior to the arrival of a shortwave. Southwesterly winds should also be breezy and combined with the forecast dry air, another day of elevated fire weather conditions looks probable. Once the wave passes through, temperatures will dip back to near normal Thursday and Friday. Morning lows these 2 days could actually be chilly in the upper 30s in eastern MN and northwestern WI. Long-range ensemble guidance favors another brief warmup for the early part of next weekend before another wave arrives. This wave should return us back to normal temperatures for early next week. However, the mild, dry weather doesn`t appear to end as long-range guidance suggests another upper-level ridge building over the northwest CONUS and traveling east throughout next week. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1043 PM CDT Sun Sep 29 2024 VFR with clear sky or high clouds this TAF period. Visibility reductions are unlikely tonight due to lower dew points, but there is a small chance at usual low lying sites. This chance was too low for inclusion in the TAFs. The biggest impact this period will be the wind shifts as a front moves through. This will include a period of atypical southwest winds which could result in the use of crosswind runways at many airports. KMSP...Main impact will be the changing winds creating a period of gusty crosswinds in the afternoon and evening. If gusts over-perform it will be around thresholds for the use of the crosswind runway. /OUTLOOK FOR KMSP/ TUE...VFR. Wind NW 10-15 kts. WED...VFR. Wind S 10-15G25 kts. THU...VFR. Wind NW 10-15 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...Fire Weather Watch from 11 AM CDT this morning through this evening for Brown-Chippewa-Douglas-Kandiyohi-Lac Qui Parle-Martin-Meeker-Pope-Redwood-Renville-Stearns-Stevens- Swift-Todd-Watonwan-Yellow Medicine. WI...None. && $$ DISCUSSION...CTG AVIATION...NDC