High pressure builds in through the weekend bringing cold, dry conditions and deteriorated marine conditions. Rain chances increase again early next week and a warming trend ensues.
Today As of 940 AM Saturday, Clear skies through much of the region as a cold Canadian high pressure builds in. Stronger CAA and dry advection regime continues behind the upper trough which moved through the region Friday evening. Caa ushers in a chilly day today, with highs in the mid to upper 40s for much of the region. Nw gusts 15-25mph this afternoon will keep feel like temperatures near 40 during the "warmest" part of the day. Sct/bkn scu continues to move over the Albemarle sound region this morning, with mostly clear skies elsewhere. Obx will see higher wind gusts due to the deepening low offshore and high building in. Nw gusts of 25-30mph are expected through the day for OBX. Along the coast typical CAA- driven strato-cu decks will linger.
Tonight As of 230 AM Saturday, Continued CAA and dry air advection results in cold and dry conditions tonight. Some mid and upper level clouds will move into the region as a weak mid level shortwave moves through. In addition, with a decent pressure gradient lingering, we may not truly become calm tonight. This will cause lows tonight to be tricky as we may not truly decouple if clouds remain overhead and winds remain elevated. In light of this, kept low temps tonight in the low to mid 20s inland (low 30s beaches). Of note, if the mid/upper level clouds doesn't have the anticipated impact, and/or if the winds do calm overnight, lows could fall into the upper teens inland (20s beaches). Marine stratocumulus lingers along and offshore of OBX tonight.
Sunday through Friday As of 230 AM Saturday,
key messages
- Below normal temperatures continue through early next week
- Increased uncertainty regarding temps and precip over the holidays
Early in the period, the forecast challenge will be temperatures. A cold airmass in place will support below to well below normal temperatures continuing through Monday. The coldest night of the weekend still looks to be Sunday night thanks to good radiational cooling conditions. In this type of setup, lows often end up below blended guidance. Interestingly, though, recent guidance has trended a touch "warmer" Sunday night, and the forecast will reflect this trend to some extent. That said, because of the expected radiational cooling effects, I don't want to latch onto the recent trend too quickly. It will be cold regardless, but if the recent trend holds, we may not quite get to Cold Weather Advisory criteria. Even with the bump up, inland lows should still easily fall into the teens, with 20s elsewhere. Headline or not, the key message is still the same, it will be cold.
Early next week, return flow develops as high pressure shifts offshore. This combined with rising low-level thicknesses should lead to gradually moderating temps. However, given the cold airmass in place, we most likely will not jump right back to climo. Within the developing return flow, a coastal trough is forecast to develop offshore Monday night into Tuesday. A shortwave is then forecast to drop southeast out of the Great Lakes, which should push the trough further away from the coast. Prior to then, modest low-mid level moisture advection may combine with the coastal trough to support a chance of showers. The best chance appears to be focused along the coast. However, depending on the track and strength of the Great Lakes wave, the chance of showers may extend north into the remainder of ENC on Tuesday. It's unclear how quickly the chance of showers will decrease later Tuesday into Christmas Eve. If the Great Lakes wave is stronger, then there would be a more clean, and quicker, end of the precip. Should that wave not be as strong, the shower risk may linger longer into the evening.
From Christmas Day through the end of the week, medium range guidance has become much more chaotic, and is in less agreement compared to previous runs. In general, guidance appears to be trending more amplified with ridging over the eastern U.S., which would tend to keep the storm track to the W and NW of ENC, and consequently keep the chance of showers lower. However, we'll continue to advertise a low chance of showers through the week as not all guidance is dry. The drying trend is notable, but not a certainty just yet. What appears more certain is a steady moderating trend, with highs getting back into the 50s and 60s, with lows in the 30s and 40s. This puts us close to climo for the end of December.
15z Saturday through Wednesday Through 12z Sunday As of 645 AM Saturday, VFR conditions present through the area with this update, with light to calm winds and 5-7kft CIGs moving through the coastal plain, from north to south. Chances of these clouds dropping to sub VFR are less than 10%. Skies clear and NW winds pick up in the afternoon and early evening hours Saturday, with gusts of 15-20kt possible for all TAF terminals. Few/sct mid and upper level clouds make their way over the region Saturday night as winds become light to calm with the loss of daytime heating.
OBX will be gustier than inland locales through the TAF period, with 15-25kt gusts from the NW through the morning increasing to 20-30kt gusts from the NW during the afternoon and evening. Saturday night gusts ease a bit again, becoming 15-25kt, still from the NW. Caa regime will promote marine stratocumulus development over coastal waters off of NOBX and Hatteras Island, with drops to MVFR CIGs possible over the waters Saturday afternoon through Saturday night.
12z Sunday through Wednesday As of 230 AM Saturday,
key messages
- Sub VFR conditions possible early next week
High pressure is expected to dominate the region over the next several days, with mostly VFR conditions. However, a coastal trough may impact the area early next week with low CIGs and a chance of SHRA. Guidance doesn't always handle coastal troughs well days in advance, but the potential is worth noting.
Through tonight As of 940 AM Saturday, Marine conditions continue deteriorating across area waters this morning as low pressure off the northeast deepens and sends northerly swell and strong NW winds our way. Latest obs show NNW winds 15-25kt with seas 5-8 ft north of Ocracoke and 3-6 ft south. Seas will continue building through the day, and by Saturday afternoon, seas north of Hatteras will be around 6-8 feet. Winds will remain elevated through today into tonight before finally easing up as high pressure dominates and the low moves further away.
SCA has been extended for the Croatan/Roanoke sounds until 7AM Sunday. No other changes made to the collection of SCAs with this update.
Sunday through Wednesday As of 230 AM Saturday,
key messages
- Improving boating conditions expected after Sunday
High pressure is likely to dominate much of the ENC waters through the holidays, which should support improving boating conditions once we get past this weekend. That said, a coastal trough is expected to develop Monday night and potentially linger through Tuesday or Wednesday. While the trough will help tighten the gradient, and support modest northeasterly winds, it appears that most of the week will feature sub SCA conditions. That is the most likely scenario, but of note, some guidance try to develop a weak coastal low along the trough. Should that occur, there would be an increased risk of SCA conditions for a portion of the waters. Otherwise, northeasterly winds of 10-20kt will be common through the week. Seas of 4-7 ft on Sunday are expected to lay down to 2-4 ft by Monday, and remain in the 2-4 ft range for much of the week.
Nc, none. Marine, small craft advisory until 4 pm EST this afternoon for amz131- 230. Small craft advisory until 7 am EST Sunday for amz135-231. Small craft advisory until 7 pm EST Sunday for amz150. Small craft advisory until 4 am EST Monday for amz152-154. Small craft advisory until 10 am EST Sunday for amz156-158.
