textproduct: Wakefield

WHAT HAS CHANGED

Updated Aviation section for 12z TAFs

KEY MESSAGES

1) Widely scattered showers and isolated storms are possible this afternoon and evening. Next chance of widespread rain Sunday night and Monday.

2) Seasonable temps Tuesday through Friday with another chance of rain and potential storms Wednesday/early Thursday.

DISCUSSION

As of 310 AM EDT Saturday...

KEY MESSAGE 1...Widely scattered showers and isolated storms are possible this afternoon and evening. Next chance of widespread rain Sunday night and Monday.

The axis of a relatively weak mid level trough along with embedded shortwaves will pivot over the east coast today. This, along with the moisture return via southerly sfc flow, may be enough to trigger a few showers today. However, the strongest forcing is split to the FA's north and south and despite increasing dewpoints, the overall moisture profile is rather dry. Therefore, coverage should be rather low. Best chance at rain or even an isolated thunderstorm will be immediately along the coast (~30% PoP) and up on the MD Eastern Shore (40-50% PoP) this afternoon. Otherwise, expecting a mild and breezy day. Highs will be in the upper 70s and winds will gust 20-25mph. Pleasant weather continues Sunday. It will be warmer with highs in the mid 80s, mostly sunny except immediately near the coast, and only light winds.

A cold front with low pressure developing along it, along with and UL trough supporting it from aloft, will bring widespread showers later Sunday night into Monday. The GEFS probs of 0.1" or greater stayed pretty steady in the 00z suite at 70-90%, but did note a downward trend in the probs out of the ECMWF Ens which dropped to less than 50% over much of the FA. As far as storm potential goes, the timing of front will make it difficult to get instability far enough north to impact any of the local area. The NAM (which does tend to run a bit hot) indicates instability making into NE NC and Hampton Roads, but it's the only one so far. Any thunderstorms that do form will likely be confined to the far SE.

KEY MESSAGE 2...Seasonable temps Tuesday through Friday with another chance of rain and potential storms Wednesday/early Thursday.

Below average temps behind the cold front expected Tues with highs in the upper 60s. Near normal temps in the mid to upper 70s then return for the rest of the week. Still looking at another front moving through the area Wednesday into Thursday bringing a round of showers and maybe some thunderstorms. Still a lot of uncertainty around whether or not we can get strong storms out of the system. The 00z guidance suite continues to show a strong UL trough with the UL low potentially dipping as far south as the Mid- Atlantic. This flow would support strong storms, but the potential overnight timing would very much limit instability. Still certainly worth keeping an eye on as a timing shift of 12 hours or so could raise severe potential.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

As of 640 AM EDT Saturday...

VFR conditions prevail for the 12z/09 TAF period. SCT-BKN high level cloud cover is spread across the region and will persist through the evening. A weak system passing overhead may spark a isolated showers today. Seeing some widely scattered showers over NE NC already, but overall impact to terminals should be low. Maintained the Prob30s to ORF, ECG, and SBY, but did bump the timing a little earlier for ECG based on radar trends. SSW winds become breezy this afternoon with gusts of 15-20kt, then diminish again after 00z.

Outlook: An area of low pressure approaches the region late Sunday into Monday, bringing the potential for additional showers and flight restrictions.

MARINE

As of 555 AM EDT Saturday...

Key Messages:

- Have ended all remaining SCAs across the mid/upper Bay. Sub- SCA conditions should prevail through Sunday night. - Small Craft Advisories are likely Monday into Tuesday, with increasing N winds, as deepening low pressure moves offshore, followed by high pressure building in from the NW. The latest wx analysis depicted high pressure well offshore, and low pressure across the upper Great Lakes. A somewhat compressed pressure gradient remains in place, allowing for elevated S winds, but have allowed the remaining SCAs to end with just a few gusts to 20 kt in the Bay. Across the northern coastal waters, a few gusts up to 20-25 kt are possible today, with seas around 4 ft, while conditions farther south will have seas 2-3ft (in general this has trended slightly weaker so no headlines will be issued). Fairly benign marine conditions are then expected tonight and Sunday as the pressure gradient weakens considerably, allowing for an aftn sea/bay breeze with winds becoming E-SE at ~10 kt.

The better chance for a more significant event arrives Monday into Tuesday, as low pressure deepens while tracking along an advancing frontal boundary, and continues to intensify offshore Mon night as the next area of high pressure builds in from the NW Tuesday. There are some model differences with respect to timing and the exact position of the sfc features, but with good model agreement that the sfc low tracks through the Carolinas, northerly winds are anticipated, along with ample mixing, so SCA headlines are likely for most, if not all of the marine area. Local wind probs for 18 kt sustained winds in the Bay are >50% and probs for 25kt gusts on the Ocean are also >50% except over the far north. Gales are very unlikely unless the sfc low were to intensify much quicker than forecast with latest probs <10%. For now, have seas building to 5-6 ft nearshore in the southern VA and NE NC waters and 4-5 ft N, but a stronger low could lead to higher seas Waves in the Bay should reach 3-4 ft. Conditions improve later Tuesday as the system moves well offshore with high pressure becoming centered over the local area.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...None.