Sunrise 5:59 AM   Sunset 8:42 PM Moonrise 2:26 AM   Moonset 6:02 PM

  Print   HELP   Reset   Save   Recall  News

FXUS61 KRNK 031826 AFDRNK

Area Forecast Discussion National Weather Service Blacksburg VA 226 PM EDT Wed Jul 3 2024

SYNOPSIS
High pressure remains in control of the region's weather, allowing for dry conditions today. However, it will be slightly warmer and more humid. Shower and thunderstorm chances increase by Thursday afternoon and continue through the weekend as a front stalls in the area.

NEAR TERM /THROUGH THURSDAY/
As of 150 PM EDT Wednesday...

Key Messages:

1) Slightly warmer and more humid today.

2) Showers and storms return Thursday on Independence Day.

A subtropical ridge continues to dominate our weather pattern here in the Mid-Atlantic, but a surface high that has been just to our north slides off the east coast by Thursday and turns our surface level flow from southerly to southwesterly.
At the same time, a mid-level disturbance will move around the north side of the sub-tropical ridge and into our area sometime Thursday afternoon. This will herald the return of scattered showers and storms to the area Thursday afternoon and evening.
This won't be the only thing that could put a damper on holiday activities though. As a result of the ridge and increased southerly flow from the high off the Atlantic coast, heat and humidity will continue to rise. Heat indices east of the Blue Ridge will be in the upper 90s, and a few locations nearer central VA could see a heat index over 100. With the sun out before showers fill in, this will feel quite sweltering, and folks should remain hydrated and try to stick to shade.



SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/
As of 1215 PM EDT Wednesday...

Key Points:

1. Well above normal temperatures but with temperatures trending slightly cooler each day.
2. Heat Index values over 100 deg possible Friday afternoon east across portions of the Piedmont.
3. Daily chances of late afternoon/evening showers and storms Thursday night through Friday night.
4. Showers/Storms chances throughout the day on Saturday, ending Saturday night.

A look at the 3 July 00Z NCEP Ensemble Mean 500 mb Geopotential heights shows a building upper ridge across the west coast of the US through the period. A shortwave trough axis is expected to be over the Upper Mississippi River Valley Thursday night into Friday. This feature is expected to amplify moves slowly shift eastward eastward into the Ohio Valley through Saturday night. A ridge of high pressure remains over the Southeast US through the period. A the surface, low pressure Thursday night into Friday is expected to move through the Great Lakes region with a cold front trailing southwest into the Mid-Mississippi River Valley. By Saturday into Saturday night, this same front is expected to approach, cross and then head southeast of our region with high pressure build in behind it.

Output from the 3 July 00Z Ensemble Situational Awareness Table shows 850mb temperatures steadily increasing Thursday night through Friday. By Friday afternoon, values of +20C to +22C are expected across the area with high end of this range over the Foothills and Piedmont region of VA/NC. Here values are expected to be higher than the 99 percentile of the 30-year climatology with values over the 97.5 percentile for the remainder of the region. For Saturday, values are only slightly cooler, by perhaps 1C. This decrease places the eastern half of the region with the 90 to 97.5 percentile of the 30-year climatology.

The above scenario points towards a Friday that is expected to be a bit hotter what we are expecting on Thursday. Given values are expected to be well into the top end of the 30-year climatology, guidance is likely to be too cool, gravitating towards values closer to climatology. Our forecast will continue to offer temperatures a few degrees above the deterministic model output. Temperatures are expected to remain well above normal for Saturday, and still a bit above normal for Sunday. A concern for Friday will be the heat index value. Many locations with the Lower James, Lower Roanoke and Dan River Valleys on Friday are expected to see the heat index value reach, or top 100 degrees. Far eastern sections of the forecast region (approximately those areas along and east of a Yanceyville, NC to Buckingham, VA line) could see values top the 105 degree mark.
If these values persist within the forecast, a Heat Advisory would be warranted for parts of most of this far eastern region as we get closer to Friday.

Precipitation chances will come in the form of showers and storms within a hot and humid airmass both in advance of an approaching cold front on Thursday night through Friday night, and then coincident to the passage of the front on Saturday. Saturday night should see rapidly decreasing chance of showers and storms from northwest to southeast as the front exits the region. Given the uncertainty in timing and location, I'll keep the POP values under the likely category at this time from Monday onward.

Confidence in the above weather conditions is moderate to high.

LONG TERM /SUNDAY THROUGH WEDNESDAY/
As of 1215 PM EDT Wednesday...

Key Points:

1. Above normal temperatures but with values trending cooler through the period.
2. After a bit of a break in showers/storm on Monday, look for a return of afternoon/evening showers/storms for the region, especially the mountains Monday through Wednesday.

A look at the 3 July 00Z NCEP Ensemble Mean 500 mb Geopotential heights shows the trough to our east is expected to remain nearly stationary, but gradually become more amplified, with high pressure remaining over the Southwest US and also over the far Southeast US. At the surface, high pressure will briefly be over the region on Sunday. A cold front is expected to move into and across our area Tuesday into Wednesday. This feature is depicted on the mean ensemble very poorly which suggested a lot of variation within the timing and strength of the system among the various model members.

Output from the 3 July 00z Ensemble Situational Awareness Table shows 850mb temperatures on Sunday are expected to range from +18C to +20C, with the high end of this range over the NC mountains. The +20C numbers touch the 90 to 97.5 percentile of the 30-year climatology. For Monday, numbers inch up a bit to the +20C to +21C range for the area, with most of the area with in the 90 to 97.5 percentile of climatology. For Monday, values are expected to be almost the same, but perhaps +19C to +21C, with the warmest sections in the east. On Wednesday, temperatures slide a bit more, with numbers in the +17C to +19C range.

Temperatures through this portion of the forecast will still be above normal, but just not as high as the end of the current week.
High pressure entering the region will bring a bit of a break to the shower and storms activity for Sunday. However, southern sections may still be close enough to the departing front for some isolated to scattered afternoon coverage.

On Monday, a cold front will approach our region, arrive on Tuesday, and perhaps linger overhead through Wednesday. The result will be a return of primarily afternoon/evening showers/storms for the region, with the best coverage over the mountains. Additionally, the greater expanse of clouds and the precipitation chances will also partially responsible for the expected slightly cooler temperatures.

Confidence in the above weather scenario is moderate.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/
As of 200 PM EDT Wednesday...

VFR conditions through the next 24 hour period. Winds will veer from generally out of the south this afternoon to southwesterly during the overnight period as high pressure moves to our east.

Some mid-level clouds will begin to fill in from the northwest in the early morning hours Thursday. There is a slight chance of showers and storms beginning in WV, potentially impacting BLF and LWB before 04/18Z, but confidence is low that it will begin that early, as such precipitation is not listed in the TAF.

Confidence in the above forecast is above normal.

OUTLOOK WEDNESDAY NIGHT THROUGH SUNDAY...

Independence Day: Odds of SHRA/TSRA increase from the NW by early afternoon as energy aloft sinks south. Flight category reductions of MVFR or lower will be possible, initially at BLF/LWB followed by BCB, ROA, LYH, and DAN.

Friday-Sunday: SCTD SHRA/TSRA remain possible as a storm system continues impacting the region. Flight category reductions remain possible.

CLIMATE
As of 200 AM EDT Wednesday...

Record highs and warmest lows temperatures for July 4th and 5th.

Thursday 07/04/2024 Site MaxT Year HiMin Year KBLF 92 1957 68 2018 KDAN 99 1925 74 1999 KLYH 98 1966 76 1902 KROA 99 1999 74 2018 KRNK 94 1966 71 1941

Friday 07/05/2024 Site MaxT Year HiMin Year KBLF 93 1948 71 1969 KDAN 103 1919 76 1926 KLYH 98 2012 75 1900 KROA 100 1999 76 2012 KRNK 94 1930 78 1949

RNK WATCHES/WARNINGS/ADVISORIES
VA...None.
NC...None.
WV...None.

Falling Creek entrance
Click for Map
Wed -- 02:15 AM EDT     4.06 feet High Tide
Wed -- 03:21 AM EDT     Moonrise
Wed -- 05:53 AM EDT     Sunrise
Wed -- 09:49 AM EDT     0.20 feet Low Tide
Wed -- 02:54 PM EDT     3.24 feet High Tide
Wed -- 06:57 PM EDT     Moonset
Wed -- 08:34 PM EDT     Sunset
Wed -- 09:37 PM EDT     0.38 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Falling Creek entrance, James River, Virginia, Tide feet

Lower Rocketts
Click for Map
Wed -- 02:44 AM EDT     4.06 feet High Tide
Wed -- 03:21 AM EDT     Moonrise
Wed -- 05:53 AM EDT     Sunrise
Wed -- 10:25 AM EDT     0.20 feet Low Tide
Wed -- 03:23 PM EDT     3.24 feet High Tide
Wed -- 06:57 PM EDT     Moonset
Wed -- 08:34 PM EDT     Sunset
Wed -- 10:13 PM EDT     0.38 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Lower Rocketts, James River, Virginia, Tide feet

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Wakefield, VA,