Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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261 FXUS63 KFGF 071935 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 235 PM CDT Sun Jul 7 2024 .KEY MESSAGES... - Scattered thunderstorms this evening will produce the main hazards of lightning and brief heavy rainfall. Additional scattered afternoon thunderstorm activity into Monday and Tuesday. - Heat builds in for Friday and Saturday with highs in the upper 80s and 90s along with humidity. && .DISCUSSION... Issued at 235 PM CDT Sun Jul 7 2024 ...Synopsis... Broad trough over the north central CONUS with one main vort over central MN, and another over northeastern SD. Several more weak shortwaves/vorts expected to come down as flow starts to transition to more northwesterly early in the work week. Upper ridging currently over the west coast begins to shift eastward later in the week, with some pretty strong 500mb heights moving into the Plains by Saturday. Some ridge riding shortwaves will also be possible during this period but predictability is low. Scattered thunderstorms tonight and again Monday/Tuesday...With just enough daytime heating for some low level instability and the upper system spinning over the region, conditions have been favorable for funnel clouds with non-supercell tornado parameter around 6 to 8 in southeastern ND. There was a funnel cloud report just before 18Z north of Fargo, and with continued shower and thunderstorm development and plenty of surface vorticity, it will be possible to see some more. Have an SPS out through 00Z highlighting the possibility of brief, low impact funnels or brief tornadoes. Threat should dissipate as soon as we lose heating. The main vorts will transition off to the east tonight into tomorrow, leaving flow over our area northwesterly. However, there will still be some weak disturbances coming down out of Canada and with cooler air aloft enough heating during the day to get scattered afternoon showers and thunderstorms going again. CAMs and larger scale models are in pretty good agreement on having at least some chances of precipitation tomorrow afternoon and again Tuesday afternoon. Like today and yesterday, there will be some decent CAPE values available around 1000-1500 J/kg but shear continues to look weak, under 20 kts. Lightning and brief heavy rainfall will again be the main threats. Heat Late Week...Upper ridge builds strongly into the area, with southerly winds picking up. Probabilities of over 90 degrees are over 40 percent in portions of the Red River valley for Friday and into next weekend. R and M climate percentiles are also showing a signal for high heights and warmth, although just 90th percentiles and not maxed out. NWS HeatRisk map has portions of our area in the major category for Saturday, so will have to watch the later part of the week closely for impacts. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1236 PM CDT Sun Jul 7 2024 All sites VFR with some shower activity at the Red River and MN airports. Some strengthening of the convection will be possible in the next few hours, so kept VCTS mention at KFAR, KTVF, and KBJI as thunderstorm cells develop and wrap around an upper low over central MN. Convective activity should taper off by early evening. Winds will remain below 10 kts through most of the period. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...JR AVIATION...JR