Marine Weather and Tides
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.
|Sunrise 6:17AM||Sunset 8:34PM||Sunday July 25, 2021 11:16 AM EDT (15:16 UTC)||Moonrise 9:09PM||Moonset 6:44AM||Illumination 98%|
7 Day Forecast for Marine Location Near Roanoke, VAHourly EDIT Help
Area Discussion for - Blacksburg, VA  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXUS61 KRNK 251400 AFDRNK
Area Forecast Discussion National Weather Service Blacksburg VA 1000 AM EDT Sun Jul 25 2021
SYNOPSIS. Showers and thunderstorms will become more widespread as a cold front passes over the Mid Atlantic during tonight into Monday. This front will stall over the Southeast by the middle of this week, while more disturbances pass over the Northeast.
NEAR TERM /THROUGH TONIGHT/. As of 1000 AM EDT Sunday .
Showers and thunderstorms will increase today as a cold front approaches from the north.
Patchy fog from this morning has given way to some clouds across the Mid Atlantic due to upstream convection from a cold front crossing over the Ohio River Valley. While any convective activity may be suppressed during most of the morning, instability and moisture should increase by midday. Scattered showers and thunderstorms are expected in the afternoon across the mountains, and some of the high-resolution models indicate a line of storms crossing into the Piedmont by the evening. An isolated strong storm could produce damaging winds and localized heavy rain that may lead to flash flooding.
Tonight the cold front to our north sinks closer but should remain to our north until daybreak Monday. Showers and isolated thunderstorms should begin to break out in the early morning hours Monday over SE WV and northwestern VA, but will generally stay north of I-81 until later. Overcast skies will keep overnight lows slightly warmer than the last couple nights.
SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/. As of 145 AM EDT Sunday .
Potentially strong and heavy rain producing showers and storms for Monday .
On Monday into Monday evening, we'll be watching a cold front head south toward and then into the area, but then stall as a shortwave trough from the Lower Ohio Valley heads east along the front.
The combination of the location of the front and this wave moving along it will equal high chances likelihood of showers and storms across the forecast area. In addition to the position of the front acting as a focus for moisture pooling, precipitable water values in advance of the front are expected to climb into the 1.50 to 2.00 inch range across the area, with the highest values across the southeast parts of the region. A look at the SPC Sounding Climatology Page puts the forecast amount of around 1.75 inches for KRNK right around the Daily Max moving average for July 26th. Also, the NAEFS PW standardization anomaly chart has the 1.50 to 2.00 inch range within the plus one sigma category immediately in advance of this front. Finally, 850-300mb bulk shear is around 30 kts Monday afternoon and nearly parallel to the expected orientation of the cold front. This pattern will be favorable for training of cells, thus promoting better chances for a locally heavy rain for parts of the area.
From a severe standpoint, afternoon forecast MUCAPE values are expected to be around 2000 J/kg across the far southeast portion of the forecast area and decrease to around 1500 J/kg near the VA/WV state line. Effective bulk shear is not expected to be large, but not non-zero either with numbers in the 25 to 30 kt range. Until the passage of the cold front, winds throughout the column are expected to be nearly unidirectional, suggest more of weak speed shear sounding versus a much in the way of directional shear. DCAPE is expected to increase to around 750 J/kg by the late afternoon, with values slightly higher across the far eastern parts of the area. The above suggests an environment where we could see some storms have decent updrafts, then collapse and produce strong straight line winds.
Monday night expect a general trend of decreasing coverage of showers and storms from north to south as the front makes slow progresses south. However, its position is not expected to be far enough south, not to be a focus for additional shower and thunderstorm development on Tuesday, especially across the southern half of the region.
For Tuesday night into Wednesday night high pressure builds into the region with drier conditions. However, with more sunshine available and lower dew points, look for a trend for higher highs and lower lows as compared to Monday.
Temperatures during this portion of the forecast are expected to average close to five degrees above normal.
Confidence in this portion of the forecast is moderate.
LONG TERM /THURSDAY THROUGH SATURDAY/. As of 115 AM EDT Sunday .
A cold front will cross the region on Friday .
During this portion of the forecast, high pressure will be in control of our weather pattern on Thursday, providing for a mainly dry and warmer than average day. Some late day isolated showers and storms will be possible over parts of southeast West Virginia, the portion of our area nearest an approaching cold front.
A cold front is expected to move through the area late Thursday night into Friday. Look for increased coverage of showers and storms, especially Friday afternoon when some of the guidance indicates the front will be crossing the southern parts of the area during the peak heating of the day.
Friday night into Saturday offers some questions in the forecast as a lot will depend upon just how far south of the region the cold front will progress. Most guidance offers solutions that continue to show the front's influence as a focus for convection across parts of the area into Saturday, especially across western and southern parts of the area.
The same question of frontal position and influence on our weather pattern will continue into Sunday. While guidance is suggesting a position farther south than Saturday, most offer solutions that are not far enough south for no influence.
Temperatures during this portion of the forecast are expected to average close to five degrees above normal Thursday and Friday, but closer to normal for Saturday and Sunday.
Confidence in this section of the forecast is on the low end of moderate. The biggest question as discussed above is the progression of the front and its subsequent influence on our weather.
AVIATION /14Z SUNDAY THROUGH THURSDAY/. As of 200 AM EDT Sunday .
Lingering showers east of Lynchburg will continue to diminish and move east. Patchy fog has already developed and will continue through the early morning hours. There is also some leftover MVFR ceilings which may impact BLF due to a passing low layer of stratocumulus clouds. Any low clouds and fog should wane after sunrise, and high clouds will begin to increase from the west due to an approaching cold front. Showers and thunderstorms will develop again by 16-18z for LWB/BLF/BCB/ROA and are expected to impact LYH and DAN around 18-21Z, although at this time PROB30 or VCTS looked sufficient for most sites.
A cold front approaches after dark, and models have ramped up rain and thunderstorm chances again by 03Z for BLF and LWB.
Extended Aviation Discussion .
The aforementioned front will continue to push south Monday and Monday night, which will bring periods of IFR/MVFR conditions from low clouds along with scattered showers and thunderstorms to most TAF sites. The cold front will stall to our southeast my mid week, possibly bringing some drier weather to northern terminals, but possible -TSRA to DAN and LYH. Another frontal system arrives for the end of the week.
RNK WATCHES/WARNINGS/ADVISORIES. VA . None. NC . None. WV . None.
SYNOPSIS . PW NEAR TERM . PW/SH SHORT TERM . DS LONG TERM . DS AVIATION . SH
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Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports. Follow links for more data.
|Roanoke, Roanoke Regional Airport, VA||3 mi||22 min||SW 9||10.00 mi||Mostly Cloudy||84°F||69°F||61%||1015.7 hPa|
|Virginia Tech Airport, VA||24 mi||21 min||W 4||10.00 mi||Fair||79°F||72°F||79%||1019.6 hPa|
Link to 5 minute data for KROA
Wind History from ROA (wind in knots)
|1 day ago||Calm||S||S||S||E||E||E||SE||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||S|
|2 days ago||W||S||NE||Calm||SE||SE||SE||Calm||N||Calm||W||Calm||NW||Calm||Calm||Calm||Calm||W||Calm||S||NE |
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