Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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168 FXUS66 KMFR 091158 AFDMFR Area Forecast Discussion National Weather Service Medford OR 458 AM PDT Sun Jun 9 2024 Updated AVIATION Section .DISCUSSION...Yesterday was the most active day in terms of thunderstorm activity. Just over 500 lightning strikes were recorded yesterday ending at midnight, with over 400 of those strikes concentrated in Klamath and Lake Counties. Shower and thunderstorm activity is continuing overnight tonight into the early morning hours, though thunderstorms have certainly diminished in coverage. As of this writing (~3am PDT), there has only been about 20-25 lightning strikes since midnight associated with activity across northern Klamath and Lake Counties. The forcing mechanism for all this activity is a weak, but not insignificant, trough that is moving into the region this morning. We do expect showers and isolated thunderstorms to continue through the morning hours, mainly across northern portions of the forecast area. As this trough pushes farther inland, shower and thunderstorm activity will increase again later today. The focus of activity will be shifted somewhat eastward today, mainly over Lake and Modoc Counties, with some isolated potential extending westward into Klamath County. We do expect the greatest coverage of showers/thunderstorms to be somewhat earlier today compared to previous days, peaking in the early afternoon vs late afternoon/evening as in previous days. We could see some strong storms today, but the chance for severe is fairly low (5 to 10%). While the atmosphere is fairly similar to previous days with similar CAPE and LI values, bulk shear is weaker today, around 20 to 30 kts, and the forcing mechanism is moving through early enough in the day to limit the peak heating contribution. Regardless, with any thunderstorms that develop today, expect strong gusty winds as well as the potential for hail. Aside from convective activity, the general cooling trend will continue today. The most notable cooling is expected east of the Cascades where high temperatures are expected to be about 7 to 10 degrees cooler. West Side will cool further as well, but only by a few degrees. The trough will push the moist unstable air and associated shower/thunderstorm activity east of the area by early this evening, and the atmosphere will stabilize for much of the week. We`ll see a transition to zonal flow on Monday, but heights will build with some semblance of a flat ridge over the region. This west to east flow will maintain a stable air mass through at least mid week, so we`ll lose the thunderstorm potential after today. Additionally, we don`t expect any sharp warm ups through then, but with building heights, temperatures will warm by a few degrees on Monday, resulting in daily high temperatures that are around 10 degrees warmer than normal Monday and Tuesday. There will be a few shortwaves that pass through in this westerly flow, bringing some slight cooling and breezy afternoon winds on Wednesday and Thursday, but conditions will remain dry through the week. A larger pattern change is looking more likely Friday into next weekend as low pressure moves into the region from the northwest. While details vary at this time, confidence is increasing a cooler pattern with temperatures trending below normal over the weekend. It`ll likely remain dry across the area, though there are some slight chances of precipitation in the forecast next weekend, favored along the coast and north of the Rogue- Umpqua Divide. Stay tuned as details become more clear. /BR-y && .AVIATION...09/12Z TAFs...Marine stratus is bringing a mix of IFR/MVFR ceilings to the coast near Brookings and also north of Cape Blanco, including North Bend, this morning. Ceilings will persist through mid-late morning, then break up to VFR. Inland, VFR will prevail through the next 24 hours. Mid-level moisture and instability associated with an upper level trough will bring isolated to scattered showers and thunderstorms east of the Cascades again today, but especially this afternoon/evening. Focus areas will be in eastern Klamath and Lake counties (40-60% chance). These may briefly result in IFR/MVFR along with strong, gusty winds and hail in the strongest cells. Outside of thunderstorms, expect breezy conditions this afternoon/early this evening with gusts commonly in the 20-25kt range at all TAF sites. Some MVFR/IFR ceilings will return to the coast this evening. -Spilde && .MARINE...Updated 200 AM Sunday, June 9, 2024...Moderate west swell will move through the waters today, gradually subsiding into Monday. Meanwhile, a thermal trough will strengthen along the northern California coast resulting in gusty north winds and steep to very steep seas, mainly south of Port Orford today into Monday. Conditions will at least remain hazardous to small craft through Wednesday morning, especially south of Cape Blanco. Then, the thermal trough will strengthen further bringing stronger north winds and steep seas to all waters Wednesday afternoon and evening with possible gales and very steep seas south of Cape Blanco. -Spilde && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Monday for PZZ356-376. Hazardous Seas Warning until 11 AM PDT Monday for PZZ356-376. && $$ MNF/MAS