textproduct: Wakefield

WHAT HAS CHANGED

Rainfall totals have increased for the late weekend low pressure system this model cycle. Some outlier model solutions still show a potential for some wintry weather across the north, but rain remains the most favored precipitation type.

KEY MESSAGES

1.) Mild temperatures continue today, especially west and southwest of the Chesapeake Bay, with a chance of morning showers across southeast Virginia and northeast North Carolina.

2.) Dry conditions and near to below average temperatures prevail tonight through Saturday.

3.) Low pressure tracks across the region Sunday into Sunday night bringing the potential for widespread rainfall. Any snow or a rain/snow mix across the northern tier of the local area remains a low probability event.

DISCUSSION

As of 335 AM EST Wednesday...

KEY MESSAGE 1...Mild temperatures arrive today and continue through Wednesday.

GOES water vapor channels depict a split flow zonal pattern across the Mid-Atlantic early this morning, with a northern stream trough from the Great Lakes to the interior Northeast, and a southern stream trough lagging back over the Arklatex. Surface low pressure over northern New England associated with the northern stream trough has an associated cold front extending to the SW into northern VA. Very mild ahead of the cold front early this morning with temperatures in the upper 40s to mid 50s with a SW wind of 5-10 mph.

The cold front will briefly tap into some southern stream moisture as it slides across the region early this morning. Most CAMs depict showers developing across SE VA by 10-12z/5-7AM, and expanding in coverage as they move SE across NE NC from about 12-16z/7-11AM. However, QPF is still only expected to be around 0.1" or less. Otherwise, the sky clears out quickly from NW-SE mid-morning to early afternoon, and downsloping NW winds should help to counter any initial CAA. Temperatures will easily rise into the upper 50s to lower 60s inland W and SW of the Ches. Bay given downsloping NW flow and a warm start. Temperatures will be more challenging over the Eastern Shore and the immediate coastlines. For example Wallops Island was 37F at 200AM with a light SSW wind off the cold water, and quickly jumped 20 degrees to 57F 25min later as the wind shifted to WSW and gusted up to 20 mph. For these locations, daily maximums may be reached early this morning, before settling into the mid 40s to around 50F during the day. The wind becomes NW 10-15 mph with gusts to ~20 mph behind the cold front, and locally gusting to ~25 mph for the MD Eastern Shore. The wind will be lighter and shift to NNE across SE VA and NE NC.

KEY MESSAGE 2...Dry conditions and near to below average temperatures prevail Wednesday night through Saturday.

Stronger CAA arrives tonight bringing a return to below average temperatures to close out the week. 00z/11 EPS/GEFS continue to show temperatures generally 5-10F below average Thursday/Friday, and then trending back to around average by Saturday, with below average lows Saturday morning rising slightly above average by afternoon. This will support highs mainly in the upper 30s/lower 40s N to upper 40s/around 50F SW, with morning lows in the 20s Thursday/Friday, then lower/mid 50s (cooler NE) by Saturday after a chilly start to the day with morning lows in the 20s. EPS/GEFS show PW anomalies of 40-60% of normal Thursday, 30-40% of normal Friday, then 50-70% of normal by Saturday, so dry conditions prevail during this time period.

KEY MESSAGE 3...Low pressure tracks across the region Sunday into Sunday night bringing the potential for widespread rainfall. Any snow or a rain/snow mix across the northern tier of the local area remains a low probability event.

Confidence continues to increase that southern stream low pressure will impact the area beginning later this weekend, primarily in the Sunday afternoon to Monday morning timeframe. There remain some notable differences in evolution amongst the deterministic 00z/11 runs of the ECMWF, CMC, and GFS, with the ECMWF and CMC showing one primary 500mb trough while the GFS splits the upper trough with one piece sliding across the Mid- Atlantic and Carolinas with the other becomes a closed low dropping SE across FL heading toward the Bahamas. This results in a considerable differences with the surface low. The ECWMF/CMC have a more organized stronger surface low that tries to pull in cooler air from the retreating high to the NE, while the GFS has a weaker low moving across the southern Mid- Atlantic and Carolinas. The deterministic 00z CMC is an outlier showing significant snow across the NW half of the area, but the 00z ECMWF does change rain to snow across the Eastern Shore late Sunday night into early Monday. Looking closer at the 00z EPS and GEPS (CMC) ensembles, there are a few outlier members showing the potential for snow or rain/snow across the northern tier. The GEFS members basically have no indication of wintry weather. Overall, rain is favored with this system, but there are non-zero probs for snow across at least the northern tier of the local area. Regardless, substantial QPF is expected across the area. 00z EPS/GEFS indicate a 50th percentile QPF ranging from 0.5-0.75" N to ~1.0" S (an increase from 24 hours ago), with the 25th percentile 0.25-0.5" N to 0.5-0.75" S, and the 75th percentile 1.25-1.5" area wide. Dry conditions are then expected by Tuesday into the middle of next week as high pressure builds in behind the late weekend system.

The NBM shows high temperature ranging from the mid 40s NW to lower 50s SE Sunday with min RH values of 50-60%. This is unrealistic assuming rain begins to fall during the day Sunday, unless the system ends up being slower. Likely, high temperatures will struggle to get out of the upper 30s to lower 40s along and NW of the low track, with 50s concentrated to the SE of the low track. There is little to no CAA behind this system and temperatures are expected to moderate above average by the middle of next week.

AVIATION /08Z WEDNESDAY THROUGH SUNDAY/

As of 100 AM EST Wednesday...

High pressure is centered offshore as of 06z with a cold front approaching from the NW. VFR with a SW wind of 8-12kt. A 40-45kt LLJ in advance of the cold from will bring a period of LLWS through 09-12z. Cloud cover quickly lowers and thickens by 09z, but primarily remains VFR. Showers are possible as the cold front moves through the region from about 11-16z, with the best chc at ORF and ECG where TEMPOs have been included, with only a PROB30 at PHF. Patchy MVFR cigs are also possible, but the latest guidance has backed off substantially and depicts primarily VFR cigs. Little to no vsby restricts are expected with the showers as rainfall rates are expected to be minimal. Drier air quickly arrives later in the morning through early aftn, with the wind becoming NW/N 8-12kt, and strongest at SBY with a NW wind of 10-15kt gusting to 20-25kt. Mainly clear and VFR tonight with a light NNW wind.

Outlook: Primarily VFR conditions are expected from Thursday through Saturday night with high pressure prevailing. Widespread rain is possible by Sunday into early Monday with flight restrictions probable.

MARINE

As of 335 AM EST Wednesday...

Key Messages: - Small Craft Advisories have been issued for late tonight into Thursday afternoon for all local waters as NW winds and seas increase behind strong cold air advection.

- Sub-SCA conditions return late Thursday into the weekend as high pressure builds in. The next system approaches the area Sunday and could bring additional headlines.

Early this morning winds are SW 10-15 kt with a few gusts to 20 kt as a warm front has crossed over the area pushing north. A cold front will move through the area this morning causing a shift in the winds to become northwesterly at 10-15 kt. Substantial cold advection and stronger winds still appear to hold off until later this evening into Thursday. NW winds will increase to 15-20 kt with gusts to 25 kt in the Ches. Bay, tidal rivers, and Currituck Sound and 20-25 kt with gusts to 30 kt in the coastal waters by Thursday morning. The tidal rivers and sound may be more marginal, but given the favorable wind direction, still expecting gusts to 20-25 kt. Along with the winds increasing, waves and seas will increase to 2-4 ft in the bay and 3-5 ft for northern coastal waters and 4-6 ft for the southern waters. With this, have issued Small Craft Advisories beginning at 7 PM for the middle bay and northern coastal waters as the colder air ushers in from the north. Remaining zones will stagger in from N to S by 1 AM.

Behind the cold air advection, winds will become benign Thursday night through at least Saturday as high pressure builds back into the region. Then, the next system will approach late weekend into early next week. There is still considerable spread on when/where the low forms and subsequently tracks, but additional headlines may be needed.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 7 PM this evening to 4 PM EST Thursday for ANZ630-631. Small Craft Advisory from 10 PM this evening to 4 PM EST Thursday for ANZ632-634. Small Craft Advisory from 1 AM to 1 PM EST Thursday for ANZ633- 635>638. Small Craft Advisory from 7 PM this evening to 1 PM EST Thursday for ANZ650-652. Small Craft Advisory from 10 PM this evening to 1 PM EST Thursday for ANZ654. Small Craft Advisory from 1 AM to 4 PM EST Thursday for ANZ656- 658.