084 FXUS63 KFGF 050359 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1059 PM CDT Thu Apr 4 2019 .UPDATE... Issued at 1009 PM CDT Thu Apr 4 2019 Surface observations show reduced visibilities remaining mainly in the 3 to 5 mile range throughout eastern ND and west of the immediate RRV, and guidance suggests that widespread fog development, if it occurs, would hold off until the early morning hours. Thus will continue to monitor for additional development. Of additional interest is an area of isolated showers and thunderstorms that have advected into the Devils Lake basin late this evening. SPC mesoanalysis indicates an area of weak MUCAPE that could allow for this activity to persist for another few hours, progressing into the central valley. UPDATE Issued at 706 PM CDT Thu Apr 4 2019 Main impact overnight will be areas of fog development. As strong mid to low level warm air advection develops ahead of the approaching front, a strong low level inversion develops with a saturated boundary layer. Visibilities have begun to reduce over portions of northeast North Dakota already, and high resolution models suggest coverage of reduced visibilities to continue to increase overnight and into the early morning. There is still some uncertainty in the extent of coverage so will monitor coverage of fog development throughout the evening. && .SHORT TERM...(This evening through Friday night) Issued at 338 PM CDT Thu Apr 4 2019 Shortwave trough actively transitioning over our CWA, while southerly low level flow has developed bringing weaker WAA to our CWA. Showers continue to transition eastward, and temps have held in the mid 30s in the north, with wintry mix mainly of rain/snow where precip tracks. Some snow grains or even sleet has mixed at times with some of the showers. Short range guidance has this almost completely ending over much of the area, but may linger in our far northeast through the night into Friday morning. Winds have increased with southerly flow, with gusts 30-35 mph and possibly a few 40 mph gusts before sunset. A cold front will drop south Friday and stall with WAA still expected near our southern CWA. Easterly flow north of this front may support fog development Friday morning (especially in areas of clearing). Lows tonight may still fall near or slightly below freezing for some, but many locations may remain above freezing. Low clouds may also linger north of this front Friday, and a large spread in temps may result in far north locations during the day near 40 and south of the front in the 50s. .LONG TERM...(Saturday morning through Thursday) Issued at 338 PM CDT Thu Apr 4 2019 Saturday-Sunday night: Trough moves out of the western US, with strong WAA and moisture advection advertised to overspread our CWA. Temperatures may fall near or slightly below freezing Saturday morning, but will remain mild and above freezing through Sunday night. Daytime highs still approaching 50 for manly locations and possibly 60s in our south. Regarding precip this weekend: There are still variances in the evolution of this pattern and where synoptic/mesoscale forcing line up, but there is a strong signal between all guidance that an anomalously moist air mass will be in place with PWATs around 1" by Saturday night and Sunday morning. Widespread light precip appears likely Saturday night and Sunday, but questions remain whether this could be a more impactful system from a rainfall perspective. During that period guidance is showing widespread precip potential and NAM especially is showing potential for banding along 700MB deformation axis. Instability may be in place as well and if banding and thunderstorm activity were realized widespread moderate to locally heavy rainfall would be possible (0.5-1.0"). This signal is concerning, but confidence is not high on occurrence, coverage, or location at this time. This needs monitored closely. Monday-Thursday: Trend will be toward near normal to below normal temperatures with overnight lows below freezing. There may be a few light precip chances, but any stronger systems are shown by guidance to remain south of our region at this time. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 706 PM CDT Thu Apr 4 2019 Expect southerly winds to slowly weaken to 5 to 10 kts overnight. Low VFR to low MVFR ceilings will prevail early this evening, then deteriorate overnight to IFR and LIFR as fog spreads in along and north of Highway 200 impacting DVL, GFK, TVF, and BJI, as well as areas north. Potential exists for fog development for areas south, including FAR, but coverage is expected to be less. IFR/LIFR fog is most likely from 10z to 15z, with conditions slowly improving late in the morning. && .HYDROLOGY... Issued at 1100 PM CDT Thu Apr 4 2019 Snowmelt continues to facilitate increasing water levels across much of the southern and central Red River Basin. After a below freezing Friday night, an increase in snowmelt will trend northward this weekend as temperatures are expected to remain above freezing across the region on both Saturday and Sunday with widespread 40s and 50s for daytime highs. The southern portions of the Red River Valley including Hickson, Lisbon, Hawley, and Mapleton, are seeing water levels gradually level off; however, they are expected to remain in flood stage for the next few days. Wahpeton, Sabin, and Dilworth will see gradual decreases in water levels. All other forecast points within the Red River Valley basin are showing rising water levels. Flood warnings have been updated or issued for East Grand Forks, Shelly, Climax, Twin Valley, and Crookston as river levels are expected to increase well into flood stage within the next 7 days. Major flooding is still expected at Fargo and is now expected in Grand Forks. Ice jams remain a concern heading into the late week/weekend. Recent satellite imagery shows considerable river ice remains in the northern half of the mainstem Red River as well as many smaller tributaries. Locations that are prone to ice jam flooding, such as Oslo and Crookston, should monitor water levels closely in the coming days as ice debris slowly make their way through local waterways. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. Areal and river point flood warnings continue across portions of the region. Refer to the latest flood warnings and statements for detailed information on specific locations. && $$ UPDATE...BP SHORT TERM...DJR LONG TERM...DJR AVIATION...BP HYDROLOGY...Lynch