BULLETIN
POST-TROPICAL CYCLONE HERMINE ADVISORY NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092016
500 PM EDT SAT SEP 03 2016
...HERMINE EXPECTED TO REMAIN A POWERFUL CYCLONE OFF THE
MID-ATLANTIC COAST FOR THE NEXT FEW DAYS...
...DANGEROUS STORM SURGE EXPECTED ALONG THE COAST FROM VIRGINIA
TO NEW JERSEY...
SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...36.2N 73.3W
ABOUT 175 MI...280 KM ESE OF NORFOLK VIRGINIA
ABOUT 175 MI...280 KM SE OF OCEAN CITY MARYLAND
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...ENE OR 75 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
The Tropical Storm Warning has been discontinued for the Tidal
Potomac from Cobb Island eastward.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
* Ocracoke Inlet to west of Watch Hill
* Pamlico and Albemarle Sounds
* Chesapeake Bay from Drum Point southward
* Delaware Bay
A Tropical Storm Watch is in effect for...
* Watch Hill to Sagamore Beach
* Block Island
* Martha's Vineyard
* Nantucket
For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 500 PM EDT (2100 UTC), the center of Post-Tropical Cyclone
Hermine was located near latitude 36.2 North, longitude 73.3 West.
Hermine is moving toward the east-northeast near 12 mph (19 km/h).
A turn toward the northeast and a decrease in forward speed is
expected by Sunday, followed by a slow northward to northwestward
motion through Monday. On the forecast track, the center of Hermine
will meander slowly offshore of the mid-Atlantic coast for the next
copule of days.
Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that maximum sustained winds are near 70 mph (110 km/h) with higher
gusts. Some strengthening is expected, and Hermine is expected to
intensify to hurricane force on Sunday.
Hermine has a large wind field. Tropical-storm-force winds extend
outward up to 205 miles (335 km) from the center. NOAA buoy 44014,
located about 75 miles (120 km) east of Virginia Beach, recently
reported a sustained wind of 54 mph (86 km/h) and a gust of 67 mph
(108 km/h). The Norfolk International Airport recently reported a
wind gust of 43 mph (69 km/h).
The latest minimum central pressure based on data from the aircraft
is 997 mb (29.44 inches).
HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions will continue to spread northward
within the warning area along the Atlantic coast through Monday,
and there may be multiple occurrences of tropical storm conditions
along portions of the mid-Atlantic coast in the warning area during
the next couple of days. Tropical storm conditions are possible in
the watch area by Monday.
STORM SURGE: The combination of a storm surge and the tide will
cause normally dry areas near the coast to be flooded by rising
waters moving inland from the shoreline. Along the immediate
coastline, the surge will be accompanied by large and dangerous
waves. There is a danger of life-threatening inundation through
tonight in the Hampton Roads area, and in the next 36 hours from
Chincoteague, Virginia, to Sandy Hook, New Jersey. Persons within
these areas should take all necessary actions to protect life and
property from rising water. Promptly follow all instructions,
including evacuation orders, from local officials. There is also
the possibility of life-threatening inundation during the next 48
hours at many coastal locations between Sandy Hook, New Jersey, and
Bridgeport, Connecticut.
For a depiction of areas at risk, please see the Prototype Storm
Surge Watch/Warning graphic, which displays areas that would qualify
for inclusion under a storm surge watch or warning currently under
development by the National Weather Service and planned for
operational use in 2017. The Prototype Graphic is available at
http://www.hurricanes.gov/graphics_at4.shtml?wsurgeThe water could reach the following heights above ground if the
peak surge occurs at the time of high tide...
North Carolina sounds...1 to 3 feet
Hampton Roads area...2 to 4 feet
Chincoteague, VA to Sandy Hook, NJ...3 to 5 feet
Sandy Hook, NJ to Bridgeport, CT...2 to 4 feet
RAINFALL: Hermine is expected to produce total rainfall
accumulations of 4 to 7 inches over far southeastern Virginia and
the Atlantic coastal portion of Maryland through Monday morning.
Hermine is expected to produce total rainfall accumulations of 1 to
4 inches over southern Delaware, southern and eastern New Jersey,
and Long Island through Monday morning.
SURF: Large waves generated by Hermine will affect the U.S. east
coast from the mid-Atlantic states and expand northward along the
coast of southern New England through Monday. These waves are
likely to cause life-threatening surf and rip current conditions,
and significant beach erosion. Please consult products from your
local weather office.
NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM EDT.
Next complete advisory at 1100 PM EDT.
$$
Forecaster Brennan
POST-TROPICAL CYCLONE HERMINE DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092016
500 PM EDT SAT SEP 03 2016
Hermine has the look of an extratropical cyclone this afternoon,
with most of the deep convection situated well northeast of the
center and dry, subsiding air wrapping around the southern
semicircle. This descending air resulted in a band of very strong
winds over portions of the Outer Banks of North Carolina today, and
those winds along with SFMR data from the aircraft support an
initial intensity of 60 kt for this advisory. Hermine has an
expansive wind field, with 34-kt winds extending about 200 miles
from the center. Hermine is still expected to interact with a
shortwave trough in the next couple of days over warm SSTs, which
should result in some intensification, although the global models
are a little less bullish this cycle. The NHC forecast continues to
show Hermine at or near hurricane intensity for the next 72 hours,
with slow weakening expected thereafter.
After moving due eastward earlier today, the initial motion is now
back toward the east-northeast at around 10 kt. Hermine should turn
northward and slow to a crawl as it merges with the upper-level
trough, and the NHC track shows only 2-3 kt of forward speed from 24
through 96 hours. The spread in the track model guidance has
increased this cycle, with the UKMET and GFS now showing more of a
westward motion and are slower to begin moving Hermine
northeastward. The ECMWF has trended eastward and is much faster,
taking Hermine south of Cape Cod in about 4 days, while the GFS and
UKMET are still centered offshore of New Jersey at that time. Given
the spread, and the possibility of looping motions during the
interaction with the upper trough, confidence in the details of the
track forecast remains quite low. The new NHC track tries to
maintain some continuity with the last one, but lies to the right of
the previous one in the first 12-24 hours due to the more easterly
motion of Hermine today. The NHC forecast is close to the
multi-model consensus through 72 hours. After that time, the NHC
track is faster than the new consensus but slower than the previous
forecast, reflecting the increasing spread at those times and low
confidence in any particular solution.
KEY MESSAGES:
1. The slow motion and large wind field associated with Hermine will
result in a long duration of hazardous conditions along much of the
mid-Atlantic coast extending into southern New England through the
holiday weekend and into midweek.
2. Small changes in the meandering track of Hermine could result in
large differences in the impacts along the mid-Atlantic coast during
the next several days. In addition, there could be multiple
occurrences of tropical storm conditions in some locations within
the warning area during this time.
3. Although Hermine has become a post-tropical cyclone, NHC will
continue to issue its full suite of advisory and warning products as
long as the system remains a significant threat to land areas.
4. P-surge, the model that drives the Potential Storm Surge Flooding
Graphic, is designed for a wind field typical of a tropical cyclone.
The wind field of Hermine is very poorly represented by the P-surge
model and as a result, Flooding Graphics prior to today's 11 am
EDT advisory understated the inundation risk from the Carolinas
northward. The NWS is using the GFS ensemble system instead of
P-surge for ongoing issuances of the Potential Storm Surge Flooding
Graphic to provide a more realistic depiction of the threat.
5. The Prototype Storm Surge Watch/Warning Graphic accounts for
the current wind structure of Hermine, and therefore accurately
identifies those areas at risk for life-threatening storm surge.
This graphic will also continue to be produced for Hermine.
FORECAST POSITIONS AND MAX WINDS
INIT 03/2100Z 36.2N 73.3W 60 KT 70 MPH...POST-TROPICAL
12H 04/0600Z 36.8N 72.0W 60 KT 70 MPH...POST-TROPICAL
24H 04/1800Z 37.2N 71.3W 65 KT 75 MPH...POST-TROPICAL
36H 05/0600Z 37.7N 71.6W 65 KT 75 MPH...POST-TROPICAL
48H 05/1800Z 38.0N 72.0W 65 KT 75 MPH...POST-TROPICAL
72H 06/1800Z 38.8N 71.9W 60 KT 70 MPH...POST-TROPICAL
96H 07/1800Z 40.0N 71.0W 55 KT 65 MPH...POST-TROPICAL
120H 08/1800Z 41.0N 68.5W 50 KT 60 MPH...POST-TROPICAL
$$
Forecaster Brennan
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