textproduct: Wakefield

WHAT HAS CHANGED

Rain chances have slightly decreased for Tuesday and there continues to remain uncertainty for the possible severe threat Wednesday and rain chances this weekend.

Marine Updates: All Coastal Flood Statements have ended. SCAs remain in place for the mouth of the Bay into Tue morning, and the Ocean into early Wed. All other SCA headlines have been discontinued.

KEY MESSAGES

1) Clear,dry, and cool tonight. A few showers are possible in the Piedmont tomorrow, but any rain amounts appear very light.

2) Widespread showers and a few storms are expected Wednesday. Some potentially maybe strong to severe but there continues to remain uncertainity

3) Mainly dry to end the week, with rain chances returning by Saturday, though drought conditions are also likely to persist. Temperatures hover near or just below seasonal averages.

DISCUSSION

As of 325 PM EDT Monday...

KEY MESSAGE 1...Clear,dry, and cool tonight. A few showers are possible in the Piedmont tomorrow, but any rain amounts appear very light.

Afternoon weather analysis shows an upper level ridge centered over the Mid-Atlantic and negatively tilted shortwave trough over the Mississippi River Valley. At the surface, a broad high pressure is overhead leading to clear skies and warmer temperatures than yesterday. As of 2pm temperatures are ranging in the middle 60s inland and lower 60s along the coast due to the onshore flow. High pressure will remain overhead tonight allowing winds to calm and strong radiational cooling to occur. Temperatures tonight will drop into the upper 30s to low 40s inland and middle to upper 40s closer to the coast. No frost is expected tonight as temperatures are just a few degrees to warm even though the RH tonight will be near 100%

For tomorrow, high pressure still remain in the vicinity of the Mid- Atlantic but will slowly move offshore. The high pressure should keep the majority of the CWA dry. However, a chance of showers remain in the forecast with the best chance west and along I-95. Since the last forecast update CAMS have backed off on the precipitation chances due to the high pressure continuing to linger in the area. However, most of the CAMS are struggling to capture the ongoing environment especially across the Mississippi River Valley. If the high pressure slides further offshore and there is more convection than previously progged (Monday into Tuesday) across the Mississippi River Valley than shower chances could increase across the west. Trends in real time and models will continue to be monitored. In terms of QPF amounts, majority of the models continue to show meager amounts less than 0.1" across the west. Otherwise, clouds will increase from the west through the day and highs will be between the upper 60s to low 70s.

KEY MESSAGE 2...Widespread showers and a few storms are expected Wednesday. Some potentially maybe strong to severe but there continues to remain uncertainity

Primarily zonal flow aloft will be over much of the area Wednesday with strong diffluence aloft. At the surface, a low pressure system is expected to track just west of the Appalachian mountains across Ohio and ino the Northeast. As the low tracks north a warm front is progged to move through bringing a slug of moisture across the area. Most models have dew points in the lower 60s across the area. Through the day showers and possible storms (later in the day) are forecasted. In terms of QPF amounts there still remains a level of uncertainty. Overall, the ensembles are on board with over 0.10" inches of rainfall. However, for anything over 0.50" there remains disagreement. The EURO ensemble looks to be the most excited with wide spread probs of40-50% while the Canadian and GFS ensembles show 10-20%. Any of the higher amounts is most likely to be colocated with the stronger convection.

Now in regards to the potential for convection, there continues to remain uncertainty with the amount of instability. This is due to the morning/afternoon showers and clouds lingering allowing for any instability to remain minimal. Will note that most short range models do have the clouds and showers breaking up allowing for weak instability building in across the area ahead of the cold front. If this is to happen and given modest shear (20-30kt 0-1km shear) and lapse rates (6-7 C/km) strong to severe storms are possible. If a sever storm is able to occur it could pose the risk of damaging wind, hail, and a possible brief tornado. As of this update and collaboration with neighbors and the SPC the marginal will remain in place across the area. However, if the uncertainties are able to be resolved there is the potential for a later upgrade.

KEY MESSAGE 3...Mainly dry to end the week, with rain chances returning by Saturday, though drought conditions are also likely to persist. Temperatures hover near or just below seasonal averages.

Zonal flow is expected to persist across the area through the end of the week and into the weekend. High pressure will slide into place Thursday and friday leading to below to near seasonable temperatures and much drier air. By the weekend rain chances increase as there could be a potential system bringing another chance of plentiful rain fall across the area. However, there remains a copious amount of uncertainty. The GFS ensemble is less suppressed with the system and has wide spread probs of 50-70% of QPF greater than 0.50". While the CMC and EURO ensembles have the system suppressed and have probs between 30-40% of 0.50" confined to the far SE. In addition to the rain chances, if this system provides beneficial rain fall this weekend it will allow for temperatures to remain much cooler than forecasted for across the area. Trends in the data will continue to be monitored as the weekend approaches.

AVIATION /19Z MONDAY THROUGH SATURDAY/

As of 1242 PM EDT Monday ...

VFR Conditions are expected through the 27/18z TAF period. NNE winds are 10-15 kt this afternoon, breeziest along the coast, with gusts to 20-25 kt at PHF, ORF, and ECG. Winds become light/calm tonight except along the immediate coast and high level clouds move across the area.

Outlook: A chance of light rain Tuesday afternoon/evening remains in the forecast with a better shot of more widespread showers and possible thunderstorms Wednesday. Flight restrictions will be minimal if they develop at all Tuesday, but are likely Wednesday into Wednesday night.

MARINE

As of 325 PM EDT Monday...

Key Messages:

- Small Craft Advisory (SCA) headlines remain in effect for the mouth of the Bay/Ocean, but have been discontinued elsewhere.

- Nuisance-type tidal flooding is possible Wednesday night for the upper Bay.

Surface high pressure has started to settle into the local waters this afternoon, with winds decreasing to ~10 kt or less for most of the region, with somewhat higher winds of 15-20kt confined to the Ocean offshore of far SE VA and NE NC. SCAs have been cancelled for all zones minus the Ocean (mainly for seas at or above 5 ft), and for the mouth of the Chesapeake Bay where waves will linger around 4 ft tonight. Seas tonight will be highest well offshore (6-8 ft) and across the nearshore NC waters (5-7 ft). The high becomes centered farther offshore Tuesday, as the next fast moving low pressure system tracks well to our NW across Canada. Winds become E to SE but remain fairly light on Tuesday, with some onshore/Bay/river breeze enhancement late Tue aftn/evening. Seas will generally remain ~5 ft Tuesday despite the minimal winds. A stronger frontal boundary approaches from the W on Wednesday, bringing a period with elevated S-SE winds, but for the most part, this looks to stay just below SCA thresholds. Some convective enhancement is possible Wed aftn/evening that could bring locally higher wind gusts. The front moves through late Wed night/early Thursday, and a surge for NW winds of 20-25 kt is expected, so SCA headlines will likely be needed for most, if not the entire marine area.

Coastal Flooding...Predominant ebb currents led to lower than expected water levels over the past 1-2 days in the lower Ches Bay/tidal rivers despite a good surge of onshore/NE flow. No additional statements will be needed. With elevated seas into midweek, and a modest increase in southerly flow Wed, some minor to nuisance tidal flooding will be possible across the upper Bay from Lewisetta to the Bayside of the MD eastern shore with the high tide cycle Wed evening/Wed night.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 4 AM EDT Tuesday for ANZ634. Small Craft Advisory until 6 AM EDT Wednesday for ANZ650-652- 654-656-658.