954 FXUS61 KAKQ 202015 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 415 PM EDT Mon Apr 20 2020 .SYNOPSIS... High pressure builds across the region tonight. A cold front crosses the area Tuesday afternoon. Cool high pressure returns Tuesday night into Wednesday. Another low pressure system moves through the Mid-Atlantic Thursday into Thursday night. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 355 PM EDT Monday... A potent upper level trough is moving across the region this aftn, with surface low pressure intensifying well offshore. Mostly cloudy to overcast this aftn with temperatures ranging through the 50s. Light rain continues over SE VA/NE NC, and this should gradually end through 6 pm. QPE through 3 pm ranges from less than 0.1" across the far nrn tier counties, to 0.25-0.5" from central VA to the lower Ern Shore, to 0.75-1.25" for SE VA/NE NC. Low pressure will pull well away from the coast this evening. However, there is a subtle secondary trough that clips the nrn counties. This will bring some passing clouds. Hi-res guidance has shown a shower or two with this system, but PoPs have been kept below 15% at this time. Drying conditions overnight as high pressure builds in from the NW. Forecast lows tonight range from the mid to upper 40s. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... As of 355 PM EDT Monday... A cold front and vigorous nrn stream trough approach from the NW Tuesday morning, and push through the region Tuesday aftn/early evening. A deep well mixed boundary layer develops Tuesday along with MLCAPE values of 500J/kg at most during the aftn. This should result in some convective showers and perhaps a few tstms as the unstable layer does nudge above -10C. 850mb wind is progged to reach or exceed 40kt and this combined with steep low- level lapse rates could result in a few damaging wind gusts from accelerating downdrafts. Breezy Tuesday with a SW wind of 15-20 mph with gusts to 25-30 mph. Seasonally mild with highs of 70-75F, with mid/upper 60s along the Atlantic coast of the Ern Shore. Any showers/tstms will be quick moving and QPF will be minimal, generally 0.1" or less. Cool high pressure builds into the region Tuesday night into Wednesday. Clear/sunny and dry with lows in the mid/upper 30s inland to low/mid 40s coastal SE VA/NE NC Tuesday night, followed by highs Wednesday in the mid/upper 50s NE to low/mid 60s SW. There is a potential for frost Wednesday morning, especially for the NW Piedmont and MD Ern Shore. High clouds increase Wednesday night as low pressure approaches from the W. Forecast lows range from the mid 40s inland to the low 50s over coastal SE VA/NE NC. The next low pressure system in this active pattern moves through the region Thursday into Thursday night. Numerical models have some timing differences, but overall, blended NBM guidance supports a 70- 90% chc of showers for the entire region during this time period. High temperatures will be somewhat challenging Thursday. An earlier arrival of pcpn would result in highs in the upper 50s/around 60F for the Piedmont, with mid/upper 50s toward the coast. A slower arrival would support warmer temperatures, especially toward the coast. Forecast lows Thursday night range from the mid 50s to around 60F. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 415 PM EDT Sunday... Went with a model blend for this period. First system pushes offshore Fri with high pressure briefly building into the area thru erly Sat before the next front crossing the region Sat aftrn and eve. Models then show an upr lvl systm moving se erly next weekend with svrl sfc trofs progged to rotate arnd the systm. Timing of these trofs rather problematic attm with pcpn chcs more likely to be diurnally driven. Thus, will carry chc PoPs Sat with the next bndry, then slght chc PoPs from Sun aftrn on given the cooler and unsettled upr lvl pattern. Highs mid 60s-lwr 70s except 60-65 Mon. Lows mid 40s-lwr 50s except 40-45 Mon. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... As of 235 PM EDT Monday... Low pressure is moving away from the Mid-Atlantic coast as of 18z. Rain continues across SE VA/NE NC, and this will gradually move offshore during the aftn ending at last ~22z for ECG. Cigs are primarily MVFR/VFR although occasional IFR cigs are expected at ECG through 20z. Occasional MVFR vsby is expected at PHF/ORF/ECG through 20z. The wind at ORF/ECG will remain NNE 10-15kt with gusts to 20-25kt through 21-22z. A secondary trough slides across the area this evening through the early overnight hours bringing some SCT mid- clouds to RIC/SBY and a very minimal chc of a shower. A cold front approaches from the W Tuesday morning and pushes through the region Tuesday aftn. This will bring a 50-70% chc of showers to SBY, and 30-40% elsewhere, along with a slight chc of tstms for the entire area. A SW wind of 15-20kt with gusts to 25-30kt is expected Tuesday aftn, and any showers/tstms could produce locally stronger gusts. High pressure returns Wednesday, with another low pressure system bringing showers and degraded flight conditions Thursday into Thursday night. Another low pressure system impacts the region by Saturday. && .MARINE... As of 355 PM EDT Monday... NNE winds are diminishing behind departing low pressure late this afternoon. As a result, have dropped all Gale Warnings and reoriented SCA headlines for next round of elevated winds expected Tuesday/Tuesday night. SCAs for the coastal waters will remain in effect through tonight for seas of 4-6 ft. Winds become SW 10-15 kt all waters overnight. Ahead of an approaching cold front Tuesday...SW winds increase to 15- 25 kt with gusts to 30 kt. Post cold front Tue night into Wed...NW winds are expected to avg 20-25 kt, except up to 30 kt with gusts as high as 40 kt north of Parramore Island. Will carry SCAs for all waters Tuesday into Tuesday night/Wed morning, except Gale Warnings north of Parramore Island from 6pm Tues-6a Wed. Waves on the Ches Bay 3-4 ft; seas 4-6 ft. Winds/waves/seas diminish/subside on Wednesday. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 10 AM Tuesday to 6 AM EDT Wednesday for ANZ635>638. Small Craft Advisory from 7 AM Tuesday to 10 AM EDT Wednesday for ANZ630>632-634. Small Craft Advisory from noon Tuesday to 6 AM EDT Wednesday for ANZ633. Small Craft Advisory until 10 AM EDT Wednesday for ANZ654-656- 658. Small Craft Advisory until 6 PM EDT Tuesday for ANZ650-652. Gale Warning from 6 PM Tuesday to 6 AM EDT Wednesday for ANZ650-652. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ/CP LONG TERM...MPR AVIATION...AJZ MARINE...JDM