Marine Weather and Tide Forecast for Roanoke, VA
November 30, 2023 5:58 PM EST (22:58 UTC)
Sunrise 7:12AM Sunset 5:04PM Moonrise 7:52PM Moonset 10:33AM
Area Discussion for - Blacksburg, VA
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FXUS61 KRNK 301935 AFDRNK
Area Forecast Discussion National Weather Service Blacksburg VA 235 PM EST Thu Nov 30 2023
SYNOPSIS
A Low pressure system over the south-central United States will move northeast tonight and cross the Mid-Atlantic Friday.
This will result in increasing cloudiness tonight and an opportunity for rain Friday. Rain amounts from this system are expected to be light, generally less than a quarter inch.
Remnants of this feature will linger through the weekend, maintaining an abundance or cloud cover.
NEAR TERM /THROUGH FRIDAY/
As of 230 PM EST Thursday...
Key Messages:
- Increasing clouds tonight - Chance of rain Friday
Regional soundings are dry. Only moisture of note was at 350 mb resulting in some high level cirrus and cirrocumulus. There was hodge podge of cloud formations and optical effects... sun dogs and cloud hole punches to name a few.
High pressure which has maintained our week of dry weather will finally get dislodged tonight...bumped off the coast by an approaching southern stream shortwave trof exiting the Southern Plains. This area of low pressure is expected to move northeast tonight, spreading cloud cover across our region. Moisture profiles suggest it will take until about mid-day Friday before any meaningful rain begins to fall. Anything before that is expected to be in the form of virga or very light rain. Even when it does rain tomorrow, model consensus is for less than a quarter of an inch, with ensembles suggesting a tenth of an inch or less. Regardless of the net amount, the day as a whole is expected to be cloudy and cooler...temperatures muted by the cloud cover...highs trending down 5 to 10 degrees compared to Thursday.
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/
As of 200 PM EST Thursday...
Key Messages:
1. Temperatures will trend to above normal readings 2. Multiple rounds of rain/showers are expected 3. Least amount of coverage is expected on Friday night into early Saturday
A look at the 30 November 00Z NCEP Ensemble Mean 500mb Geopotential height contour reveals the following. For the start of Friday night, a long wave trough is expected to be situated from Montana south across the Four-Corners region then to Baja California. Across our region will be a lengthly southwest flow pattern with a weak shortwave trough heading out of our region towards New England. As we progress in time, the upper trough is expected to move progress eastward, reaching central CONUS by early Sunday evening. All the while, southwest flow is expected to continue across our region.
While the flow across our region is depicted as quite parallel during the period, this likely is a result of the averaging process.
Embedded shortwaves moving through this pattern are likely, although there would appear not to be enough of a signal to render a shortwave trough within the pattern.
At the surface Friday night low pressure centered over IN/IL with a warm front extending across New England and a cold front south into the Lower Mississippi River. For Saturday, model averaging suggest a brief col over or just north of the region, with perhaps another weakness with the southwest flow over the TN/MS/AL region. However, more pronounced is a trough/cold front extending from the Northern to the Central Plains states. By late Sunday night, this same surface trough is expected to be over the Great Lakes region where averaging actually places a closed low. A surface trough extents southeast from this low to across our region.
A look at the 30 Nov 00Z NAEFS output for the Mid-Atlantic region shows the following. Precipitable water late Saturday night/early Sunday mornings values Friday night into Monday night are expected to gradually increase across the region. Values are expected to peak around the 1.00 to 1.50 inch range Saturday evening with the high end of this range across the southern portion of the region. These values correspond to the 90 to 97.5 percentile range of the 30-year normals with those areas receiving 1.50 inches touching the 97.5 to 99 percentile range. PW values slowly decrease late Saturday night through Sunday but still remain on the high side of normal for this time of year. Sunday night PW values will continue trending downward, reaching values only slightly above normal by late Sunday night. The 850mb temperature output offers a warming trend into Saturday where values are expected to climb to around +10C, or what would be the top 90 to 97.5 percentile of the 30-year climatology.
Similar values continue through Saturday night but decrease to values closer to +8C or +9C by late Sunday afternoon. By late Sunday night those values will be closer to +4 to +6C.
The above scenario points to the following forecast. For Friday night into early Saturday, we look to get sideswiped in terms of precipitation associated with the feature heading northeast through the Ohio Valley. The best dynamics and focus for moisture convergence is expected to be north of the region. However, we still should be close enough for a bit of coverage. As Saturday continues into Saturday night, the Tennessee Valley feature looks to have a better trajectory to not only bring precipitation to the area, but also work with high level of precipitable water across the region for local precipitation generation.
Sunday into Sunday night, the region will still be within a pattern conducive to additional weak features heading northeast across the region. Additionally, a Great Lakes shortwave trough may try to team with one of southern stream features. Deterministic model solutions offer a wide variety of possible interactions, thus yielding lower confidence. Temperatures should trend milder during this portion of the forecast with above normal conditions common.
Confidence in the above portion of the forecast is low to moderate.
LONG TERM /MONDAY THROUGH WEDNESDAY/
As of 200 PM EST Thursday...
Key Messages:
1. Isolated to scattered rain/snow showers expected main across the mountains Monday through Wednesday.
2. Trending colder into Tuesday, but then warming through Thursday.
3. Dry everywhere on Thursday.
A look at the 30 November 00Z NCEP Ensemble Mean 500mb Geopotential height contour reveals the following. The mean location of the axis of the longwave trough that has been moving eastward across is expected be across the central Great Lake region south into the Lower Ohio Valley, then curing slightly southwest into the Lower Mississippi River Valley. An upper ridge is expected to be building across the Pacific Northwest. On Tuesday, in response to the building ridge in the west, the upper trough near our region is not expected to move much, rather become a bit more positively tilted.
Not until Wednesday is the trough axis expected to be east of the region, near the East Coast by early evening. The upper ridge at this point will be centered across the Northern High Plains southwest towards the Four-corners region. By Thursday, the region will be in a period of transition with the ridge, closer, but still to our west, and the trough farther to our east.
At the surface on Monday, low pressure is expected to be centered near New England, with a cold front situated south along the East Coast. On Tuesday, while less defined and farther away, the low is expected to be off the coast of the Canadian Maritimes. Surface high pressure is expected to be centered over the Central Rockies with a ridge of high pressure extending southeast into Lower Mississippi River Valley. By Wednesday, the center of the high is expected to be over the Lower Mississippi River Valley. On Thursday, the high's position shifts to the Southeast US, but with notable various in the model members, the high has lost a bit of definition.
A look at the 30 Nov 00Z NAEFS output for the Mid-Atlantic region shows the following. Precipitable water values are initially slightly above normal on Monday, but fall to values around normal Tuesday and continue that way through Thursday. The 850mb temperatures are expected to initially fall then gradually moderate through the period.
On Monday, values are expected to be around -2C to +2C on a north- south gradient across the region. On Tuesday, values around -4C are more likely. Values moderate slightly on Wednesday, then by Thursday average +4C across the region.
The above scenario points to the following forecast. With the surface low to our northeast on Monday and the cold front to our east, our region will be within a northwest flow regime. This is a pattern that is expected to continue into Tuesday. This pattern should produce at least increased cloud cover across Southeast West Virginia, and neighboring portions of Southwest Virginia and south into the mountains of North Carolina. Likewise a there is good probability of at least isolated, if not scattered, coverage of rain and snow showers on Monday through Tuesday night night.
For Wednesday, we will still be dealing with the fact that the upper trough has not yet crossed the region. That is expected to happen during the day on Wednesday, with a healthy northwest flow in mid- levels continuing into Wednesday night. This pattern should continue the chances of at least isolated to scattered rain/snow showers across primarily the same regions as Monday and Tuesday. While the mountains receive isolated to scattered showers during this time period, areas east of the crest of the Blue Ridge can expect little to no precipitation. The farther east, the better the chance of dry.
By Thursday, we are expected dry and milder weather for the entire region as the upper ridge to our west builds closer and 850mb temperatures increase.
Confidence in the above weather scenario is moderate.
AVIATION /19Z THURSDAY THROUGH TUESDAY/
As of 200 PM EST Thursday...
VFR conditions are expected through the TAF forecast period.
High pressure will control our weather into tonight. Winds will favor a southwest direction with speeds around 5 to 10 kts this afternoon. Some high clouds will invade the sky today into tonight. Skies will become mostly cloudy tonight, cloud layers lowing with time, but remaining VFR in general.
Rain arrives Friday...with visibility restrictions holding off until the afternoon. Cloud bases are also expected to remain VFR until the afternoon, before lowering blo 3kft.
High confidence in Near Term Forecast.
Extended Aviation Discussion...
Sub-VFR expected Friday afternoon and into the weekend as storm system crosses the region and then stalls to our south. Clouds and potential for periods of sub-VFR possible may linger through Tuesday.
RNK WATCHES/WARNINGS/ADVISORIES
VA...None.
NC...None.
WV...None.
Area Forecast Discussion National Weather Service Blacksburg VA 235 PM EST Thu Nov 30 2023
SYNOPSIS
A Low pressure system over the south-central United States will move northeast tonight and cross the Mid-Atlantic Friday.
This will result in increasing cloudiness tonight and an opportunity for rain Friday. Rain amounts from this system are expected to be light, generally less than a quarter inch.
Remnants of this feature will linger through the weekend, maintaining an abundance or cloud cover.
NEAR TERM /THROUGH FRIDAY/
As of 230 PM EST Thursday...
Key Messages:
- Increasing clouds tonight - Chance of rain Friday
Regional soundings are dry. Only moisture of note was at 350 mb resulting in some high level cirrus and cirrocumulus. There was hodge podge of cloud formations and optical effects... sun dogs and cloud hole punches to name a few.
High pressure which has maintained our week of dry weather will finally get dislodged tonight...bumped off the coast by an approaching southern stream shortwave trof exiting the Southern Plains. This area of low pressure is expected to move northeast tonight, spreading cloud cover across our region. Moisture profiles suggest it will take until about mid-day Friday before any meaningful rain begins to fall. Anything before that is expected to be in the form of virga or very light rain. Even when it does rain tomorrow, model consensus is for less than a quarter of an inch, with ensembles suggesting a tenth of an inch or less. Regardless of the net amount, the day as a whole is expected to be cloudy and cooler...temperatures muted by the cloud cover...highs trending down 5 to 10 degrees compared to Thursday.
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/
As of 200 PM EST Thursday...
Key Messages:
1. Temperatures will trend to above normal readings 2. Multiple rounds of rain/showers are expected 3. Least amount of coverage is expected on Friday night into early Saturday
A look at the 30 November 00Z NCEP Ensemble Mean 500mb Geopotential height contour reveals the following. For the start of Friday night, a long wave trough is expected to be situated from Montana south across the Four-Corners region then to Baja California. Across our region will be a lengthly southwest flow pattern with a weak shortwave trough heading out of our region towards New England. As we progress in time, the upper trough is expected to move progress eastward, reaching central CONUS by early Sunday evening. All the while, southwest flow is expected to continue across our region.
While the flow across our region is depicted as quite parallel during the period, this likely is a result of the averaging process.
Embedded shortwaves moving through this pattern are likely, although there would appear not to be enough of a signal to render a shortwave trough within the pattern.
At the surface Friday night low pressure centered over IN/IL with a warm front extending across New England and a cold front south into the Lower Mississippi River. For Saturday, model averaging suggest a brief col over or just north of the region, with perhaps another weakness with the southwest flow over the TN/MS/AL region. However, more pronounced is a trough/cold front extending from the Northern to the Central Plains states. By late Sunday night, this same surface trough is expected to be over the Great Lakes region where averaging actually places a closed low. A surface trough extents southeast from this low to across our region.
A look at the 30 Nov 00Z NAEFS output for the Mid-Atlantic region shows the following. Precipitable water late Saturday night/early Sunday mornings values Friday night into Monday night are expected to gradually increase across the region. Values are expected to peak around the 1.00 to 1.50 inch range Saturday evening with the high end of this range across the southern portion of the region. These values correspond to the 90 to 97.5 percentile range of the 30-year normals with those areas receiving 1.50 inches touching the 97.5 to 99 percentile range. PW values slowly decrease late Saturday night through Sunday but still remain on the high side of normal for this time of year. Sunday night PW values will continue trending downward, reaching values only slightly above normal by late Sunday night. The 850mb temperature output offers a warming trend into Saturday where values are expected to climb to around +10C, or what would be the top 90 to 97.5 percentile of the 30-year climatology.
Similar values continue through Saturday night but decrease to values closer to +8C or +9C by late Sunday afternoon. By late Sunday night those values will be closer to +4 to +6C.
The above scenario points to the following forecast. For Friday night into early Saturday, we look to get sideswiped in terms of precipitation associated with the feature heading northeast through the Ohio Valley. The best dynamics and focus for moisture convergence is expected to be north of the region. However, we still should be close enough for a bit of coverage. As Saturday continues into Saturday night, the Tennessee Valley feature looks to have a better trajectory to not only bring precipitation to the area, but also work with high level of precipitable water across the region for local precipitation generation.
Sunday into Sunday night, the region will still be within a pattern conducive to additional weak features heading northeast across the region. Additionally, a Great Lakes shortwave trough may try to team with one of southern stream features. Deterministic model solutions offer a wide variety of possible interactions, thus yielding lower confidence. Temperatures should trend milder during this portion of the forecast with above normal conditions common.
Confidence in the above portion of the forecast is low to moderate.
LONG TERM /MONDAY THROUGH WEDNESDAY/
As of 200 PM EST Thursday...
Key Messages:
1. Isolated to scattered rain/snow showers expected main across the mountains Monday through Wednesday.
2. Trending colder into Tuesday, but then warming through Thursday.
3. Dry everywhere on Thursday.
A look at the 30 November 00Z NCEP Ensemble Mean 500mb Geopotential height contour reveals the following. The mean location of the axis of the longwave trough that has been moving eastward across is expected be across the central Great Lake region south into the Lower Ohio Valley, then curing slightly southwest into the Lower Mississippi River Valley. An upper ridge is expected to be building across the Pacific Northwest. On Tuesday, in response to the building ridge in the west, the upper trough near our region is not expected to move much, rather become a bit more positively tilted.
Not until Wednesday is the trough axis expected to be east of the region, near the East Coast by early evening. The upper ridge at this point will be centered across the Northern High Plains southwest towards the Four-corners region. By Thursday, the region will be in a period of transition with the ridge, closer, but still to our west, and the trough farther to our east.
At the surface on Monday, low pressure is expected to be centered near New England, with a cold front situated south along the East Coast. On Tuesday, while less defined and farther away, the low is expected to be off the coast of the Canadian Maritimes. Surface high pressure is expected to be centered over the Central Rockies with a ridge of high pressure extending southeast into Lower Mississippi River Valley. By Wednesday, the center of the high is expected to be over the Lower Mississippi River Valley. On Thursday, the high's position shifts to the Southeast US, but with notable various in the model members, the high has lost a bit of definition.
A look at the 30 Nov 00Z NAEFS output for the Mid-Atlantic region shows the following. Precipitable water values are initially slightly above normal on Monday, but fall to values around normal Tuesday and continue that way through Thursday. The 850mb temperatures are expected to initially fall then gradually moderate through the period.
On Monday, values are expected to be around -2C to +2C on a north- south gradient across the region. On Tuesday, values around -4C are more likely. Values moderate slightly on Wednesday, then by Thursday average +4C across the region.
The above scenario points to the following forecast. With the surface low to our northeast on Monday and the cold front to our east, our region will be within a northwest flow regime. This is a pattern that is expected to continue into Tuesday. This pattern should produce at least increased cloud cover across Southeast West Virginia, and neighboring portions of Southwest Virginia and south into the mountains of North Carolina. Likewise a there is good probability of at least isolated, if not scattered, coverage of rain and snow showers on Monday through Tuesday night night.
For Wednesday, we will still be dealing with the fact that the upper trough has not yet crossed the region. That is expected to happen during the day on Wednesday, with a healthy northwest flow in mid- levels continuing into Wednesday night. This pattern should continue the chances of at least isolated to scattered rain/snow showers across primarily the same regions as Monday and Tuesday. While the mountains receive isolated to scattered showers during this time period, areas east of the crest of the Blue Ridge can expect little to no precipitation. The farther east, the better the chance of dry.
By Thursday, we are expected dry and milder weather for the entire region as the upper ridge to our west builds closer and 850mb temperatures increase.
Confidence in the above weather scenario is moderate.
AVIATION /19Z THURSDAY THROUGH TUESDAY/
As of 200 PM EST Thursday...
VFR conditions are expected through the TAF forecast period.
High pressure will control our weather into tonight. Winds will favor a southwest direction with speeds around 5 to 10 kts this afternoon. Some high clouds will invade the sky today into tonight. Skies will become mostly cloudy tonight, cloud layers lowing with time, but remaining VFR in general.
Rain arrives Friday...with visibility restrictions holding off until the afternoon. Cloud bases are also expected to remain VFR until the afternoon, before lowering blo 3kft.
High confidence in Near Term Forecast.
Extended Aviation Discussion...
Sub-VFR expected Friday afternoon and into the weekend as storm system crosses the region and then stalls to our south. Clouds and potential for periods of sub-VFR possible may linger through Tuesday.
RNK WATCHES/WARNINGS/ADVISORIES
VA...None.
NC...None.
WV...None.
toggle option: (graph/table)
Airport Reports
EDIT (on/off) Help Click EDIT to display multiple airports. Follow links for more data.| Airport | Dist | Age | Wind kt | Vis | Sky | Weather | Temp | DewPt | RH | inHg |
| KROA ROANOKEBLACKSBURG RGNL/WOODRUM FIELD,VA | 4 sm | 64 min | S 05 | 10 sm | Clear | 55°F | 27°F | 33% | 30.13 | |
| KBCB VIRGINIA TECH/MONTGOMERY EXECUTIVE,VA | 24 sm | 23 min | S 04 | 10 sm | Clear | 50°F | 25°F | 37% | 30.15 |
Wind History from ROA
(wind in knots)
Blacksburg, VA,
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