Area Forecast Discussion
Issued by NWS Flagstaff, AZ
Issued by NWS Flagstaff, AZ
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270 FXUS65 KFGZ 261800 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 1100 AM MST Wed Jun 26 2024 .SYNOPSIS...Daily chances for afternoon and evening showers and thunderstorms will continue through Thursday. Activity then slowly decreases and becomes more focused over eastern Arizona by the weekend. && .UPDATE...A well developed MCV rotated through northern Arizona overnight continuing to bring areas of light to moderate rainfall. It can still be seen rotating just northeast of Flagstaff this morning. Overall, we expect less activity today than yesterday given the abundant cloud cover across north-central and northeastern Arizona, as well as likely subsidence behind the MCV. The FGZ sounding this morning indicated a couple degrees of warming aloft, meaning less instability. Nonetheless, there is still a juicy air mass in place, and areas that see some clearing will see convection develop. We expect the greatest instability today to be generally south of the Mogollon Rim and perhaps western Coconino county, where the best clearing is. This is also in line with where the CAMs project the best instability. Have updated precipitation chances today to decrease across the northeast and keep better chances south/west of the Rim. Heavy rain and flash flooding will continue to be the main concern, especially give yesterday`s rainfall. Small and gusty winds will also be possible in the stronger cells. && .PREV DISCUSSION /355 AM MST/...Today...The resulting MCV from Tuesday`s storms remains over much of northern Arizona, and should gradually lift northward into far north-central Arizona as it decays. Thus, cloud cover will remain over a large portion of the area for the overnight and into the early morning hours. Convective initiation later in the morning and into the afternoon will largely be dependent on where there is less cloud cover destabilization can occur. 00Z HREF guidance has the greatest insatiability concentrated mainly south of I-40 for the first part of the day, then gradually increasing over eastern Arizona as cloud cover begins to break. Given the still abnormal abundance of moisture, flash flooding will continue to be a threat this afternoon. A slight increase in storm motions (around 5-15 kts) will lower the threat a bit, but is largely a nominal decrease in the risk. HREF PMM guidance has the greatest threat for flash flooding mainly along the Mogollon Rim and into eastern Arizona near the New Mexico border. Thursday...A weak through brushes past Arizona on Thursday, drier more westerly flow aloft begins to set in across western Arizona. Remaining moisture over the eastern-half of the state will allow for isolated to scattered showers and thunderstorms to develop, especially over the Four Corners region. With the influence of the trough, storm motions look to increase to around 15-25 kts, thereby reducing the residency time of any one storm. Thus, the flash flood threat looks to be a bit lower, however any areas that see training thunderstorms or rain sensitive areas could see flash flooding. 0-6 km wind shear also looks to increase to around 20-30 kts over northern and eastern Arizona. The shear combined with around 1000 J/Kg of surface CAPE may lead to a increased severe threat. Thus, any stronger storm will have the potential to produce strong gusty winds and hail. Friday through Tuesday...Much drier air sets in by Friday, with the vast majority of the area remaining rain free. The only exception may be near the White Mountains where a few isolated showers will be possible during the afternoon. As the trough lifts, high pressure gradually builds back into the southwest. Moisture slowly makes a return, with chances for showers and thunderstorms increasing each day from southeast to northwest. Outside of the preciptation, temperatures look to remain near-normal through the period. Winds may be a tad on the breezier side, with peak afternoon gusts around 20-25 mph. && .AVIATION...Wednesday 26/18Z through Thursday 27/18Z...VFR conditions outside of storms. Widely scattered -SHRA/TSRA will develop across the region and persist until after 00Z. Heavier TSRA will produce sub VFR ceilings and visibilities. Winds will be light away form storms. OUTLOOK...Thursday 27/18Z through Saturday 29/18Z...Expect mostly VFR conditions away form storms that develop Thursday afternoon. Drier weather is expected Friday. Gusty/erratic winds possible near storm development, with SW winds 10-20 kts expected otherwise. && .FIRE WEATHER...Today and Thursday...Afternoon showers and thunderstorms continue. Stronger storms will bring heavy rainfall, hail, lightning, and gusty, erratic winds. On Thursday, the emphasis shifts primarily to the Mogollon Rim northeast and eastward. Winds on Wednesday will mainly be driven by outflows. By Thursday, expect southwest winds 10 to 15 mph, gusts from 20 to 30 mph, especially for the central and western zones. Friday through Sunday...Most of the central and western zones become drier, warmer and breezy. Afternoon storm chances continue for the eastern zones, but coverage becomes more isolated. Expect southwest winds 10 to 15 mph, gusts from 20 to 30 mph, each day. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...MCT/Humphreys AVIATION...MAS FIRE WEATHER...RKR For Northern Arizona weather information visit weather.gov/flagstaff