textproduct: Wakefield

WHAT HAS CHANGED

Slight (level 2/4) excessive rainfall outlook has expanded to cover most of the area on Monday

KEY MESSAGES

1) While not as hot as the past two days, heat indices peak around 105 degrees this afternoon. A Heat Advisory is in effect for most of the area.

2) Strong to severe thunderstorms are again possible today and Monday. Damaging winds remain the primary threat from storms. There is also an increased risk for flash flooding Monday.

3) Temperatures gradually trend closer to normal by early next week, with unsettled weather continuing into the midweek period.

DISCUSSION

As of 325 PM EDT Sunday...

KEY MESSAGE 1...While not as hot as the past two days, heat indices peak around 105 degrees this afternoon. A Heat Advisory is in effect for most of the area.

The upper level ridge that has produced the prolonged heat wave breaks down further today, while a weak trough slowly moves eastward in the OH Valley, allowing not as hot temperatures today. Despite the slight height falls, hot and humid conditions continue today with heat indices reaching around 106 this afternoon. A Heat Advisory remains in place for the majority of the area, except the VA Eastern Shore and NC/MD beaches, until 8 PM tonight. Showers/storms could drop the temperature this evening in areas that receive convection. No heat headlines are anticipated for Monday, as temperatures are a few degrees cooler, in the lower 90s, despite dew points rebounding to the lower to mid 70s. Convective coverage and cloud cover is expected to be higher Monday, which will also limit heat indices like the last few days.

KEY MESSAGE 2...Strong to severe thunderstorms are again possible today and Monday. Damaging winds remain the primary threat from storms. There is also an increased risk for flash flooding Monday.

Showers and storms have begun developing over the area this afternoon once again, mostly in the piedmont, and moving toward the area north of the I-64 corridor. A few models show convection developing over SE VA/NE NC, so pop up showers/storms are possible, but the decaying ridge will try to inhibit storms. Showers and storms will develop off mesoscale boundaries from yesterday and outflows boundaries. The hot and humid airmass has a very favorable environment with abundant MLCAPE and DCAPE (although slightly less than yesterday), but the lack of shear is a limiting factor. Any storm that develops could pose a risk of damaging winds and very frequent lightning. SPC has maintained a Slight Risk (level 2 of 5) for the northern tier of the forecast area, with a Marginal Risk to the S.

The weak trough axis aloft will be a little closer to the area Monday. Most models are in agreement that widespread thunderstorm development will commence by the early afternoon as surface troughing sharpens. The specific details remain unclear but the latest RRFS/REFS suite depicts storms initially forming inland and moving toward the coast by the evening. Isolated storms may become severe with damaging wind gusts. SPC maintains a Marginal Risk (level 1 of 5) for the majority of the area. There is also a flooding concern as these showers/storms will likely be slow moving and efficient rainfall producers. PWATs are expected to be over 2.0" in the afternoon/evening with an anomaly of around 150% of normal. The latest HREF highlights the majority of the area with a 30% chance of 3.0"/3 hr and localized rainfall totals of 3-4". This could lead to flash flooding, especially over urban and flood prone areas. WPC has slightly expanded the Slight Risk ERO to now cover most of the area. A Flood Watch may be needed with the next package if the trends continue.

KEY MESSAGE 3...Temperatures gradually trend closer to normal by early next week, with unsettled weather continuing into the midweek period.

A weak flow pattern very typical for the middle of summer with daily chances for showers and storms takes shape midweek. A rather high coverage of showers/storms is again expected Tuesday (PoPs ~70%) with generally chc PoPs (30-50%) Wednesday-Friday. Temperatures will also trend back toward seasonal norms for most of next week, ranging from the upper 80s to lower 90s. A weak front will cross the area Wednesday, resulting in the coolest day this week with highest in the 80s, depending on how quickly the front moves through the area.

AVIATION /06Z MONDAY THROUGH FRIDAY/

As of 130 AM EDT Monday... Primarily VFR is expected early this morning. Guidance has trended to keeping MVFR CIGs just N of SBY this morning, but will continue SCT015 mention to account for any uncertainty. Another round of storms are expected later this afternoon and evening with higher confidence that the coastal terminals see storms as well. Locally higher winds, heavy rain, frequent lightning, and reduced VSBY are likely within storms. Storms may linger into early tonight before diminishing/weakening after 06z Tuesday. Winds today will generally be out of the S-SW, but the overall flow field is quite weak and variable directions are likely in and around storms.

Outlook: Additional thunderstorms are likely Tuesday and Wednesday. Localized flight restrictions would be expected in storms, but prevailing VFR is expected outside of storms.

MARINE

As of 255 AM EDT Sunday...

Key Messages:

- Sub-SCA marine conditions are expected to prevail into early this week, with mainly south- southwesterly winds.

- Elevated wind gusts from strong thunderstorms are possible during afternoon and evening hours today and Monday.

High pressure remains in vicinity of the Southeast coast this evening into this week allowing for continued, mainly light, southerly flow. Some diurnal wind speed and direction variability is likely to prevail this afternoon/evening and Monday (mainly S-SW overnight into the morning, becoming S-SE in the late afternoon), and there will likely be a few hour period late this afternoon and evening where a SSE wind increases to 10-15kt with gusts to ~20kt. Isolated showers/storms develop this afternoon, mainly over the Chesapeake Bay and rivers, with potentially better coverage of showers/storms Monday afternoon/evening. Strong wind gusts will be possible with any thunderstorms. Seas will average 2-3 feet tonight through early this week while waves in the Chesapeake Bay will average 1-2 feet. A very weak cold front may settle into the Carolinas by the middle of the week, but sub-SCA conditions are expected to continue.

CLIMATE

Record Highs:

- Site: Sun 7/5

- RIC: 102/2012 - ORF: 98/2012 - SBY: 102/2012 - ECG: 100/2012

Record High Mins:

- Site: Sun 7/5

- RIC: 79/2012 - ORF: 80/1999 - SBY: 81/2012 - ECG: 77/2024

EQUIPMENT

KAKQ radar is down due to mechanical issues without an estimated time of return.

AKQ WATCHES/WARNINGS/ADVISORIES

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