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Category: Tropical

10 a.m. Notes on Arthur: Hurricane Strengthening, Will be Cat 2

| 10:19 am July 3, 2014

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LATE REPORT – NEW VORTEX DATA MESSAGE
…Shows pressure continues to drop. Now 980 mb.
…The SFRM instrument estimated 66 knots surface wind (77 mph).
…Max flight level wind 79 knots (92 mph).

URNT12 KNHC 031518
VORTEX DATA MESSAGE AL012014
A. 03/15:02:50Z
B. 32 deg 25 min N
078 deg 39 min W
C. 700 mb 2906 m
D. 66 kt
E. 360 deg 0 nm
F. 297 deg 62 kt
G. 199 deg 18 nm
H. 980 mb
I. 13 C / 3046 m
J. 14 C / 3046 m
K. NA / NA
L. OPEN SW
M. C30
N. 12345 / 07
O. 0.02 / 3 nm
P. AF301 1101A ARTHUR OB 04
MAX FL WIND 62 KT 199 / 18 NM 14:57:00Z
MAX OUTBOUND FL WIND 79 KT 048 / 23 NM 15:10:00Z
MAX FL TEMP 16 C 179 / 13 NM FROM FL CNTR

ORIGINAL POST
The new advisory is out on Arthur. It has intensified to 90 mph. This is nearly a category two hurricane (threshold is 96 mph).

Click image to enlarge.

Click image to enlarge.

FAST FACTS 10 AM CDT
———————————————————
LOCATION…32.4N 78.5W
ABOUT 260 MI…415 KM SW OF CAPE HATTERAS NORTH CAROLINA
ABOUT 110 MI…175 KM SSW OF CAPE FEAR NORTH CAROLINA
MAXIMUM SUSTAINED WINDS…90 MPH…150 KM/H
PRESENT MOVEMENT…NNE OR 15 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…981 MB…28.97 INCHES

…Radar motion over the past 90 minutes or so seems to have been directly north. This is troubling, since all of the forecasts are showing a northeasterly turn. That northeasterly turn was very apparent early this morning with the recon fixes showing it clearly. The official track is to the NNE. The forward speed has increased to 14 mph.

…The central pressure continued to drop all morning. The last report from the plane was 983 mb at 6:26 a.m. CDT. The Air Force Hurricane Hunter plane is penetrating the center now. The NOAA3 P-3 Orion “Kermit” returned to base in Tampa for fuel. Seeing Kermit and Miss Piggy in recon reports always makes me smile.

…The P3 did measure a 91 knot max flight level wind (105 mph) at 8,000 feet.

…From the NWS Charleston: Good morning! The eye of Arthur is looking much more impressive over the past few radar volume scans, with an intense band of convection developing just northwest of the center. Buoy 41004 has been gusting to 45 knots with seas of 14 ft! It should be noted with seas that high, the buoy is likely not sampling the winds all that well and sustained winds could actually be closer to what the buoy is reporting as gusts.

…High surf and dangerous rip currents along the coast. Isle of Palms near Charleston reporting breaking waves 5-6 feet.

…A few observations from South Carolina:
…North Myrtle Beach 75F/73F with light rain/fog, SE-8 29.95R
…Mount Pleasant 77F/73F with drizzle, N 10 G 21, 29.81F
…Charleston 80F/73F with cloudy skies, N 16 G 23, 29.84F
…Folly Beach N 24 G 29
…Buoy (41 miles SE of Charleston) gusts to 52 mph
…Frying Pan Shoals Buoy is not available

…Coastal reports from the NWS Wilmington
OTHER MARINE REPORT
NATIONAL WEATHER SERVICE WILMINGTON NC
1107 AM EDT THU JUL 3 2014

…ALL SPEEDS IN KNOTS…

WIND AIR TEMP(F) WATER TEMP(F) STATION NAME
SSW 17 80 NA NORTH TOPSAIL BEACH
SE 11 72 82 WRIGHTSVILLE BEACH
ESE 5 74 M MASONBORO ISLAND
M M 74 85 WILMINGTON RIVERFRONT
CALM 0 74 NA WILMINGTON STATE PORT
NE 6 78 NA FORT FISHER
E 10 76 NA BALD HEAD ISLAND
ENE 8 75 NA SOUTHPORT
M M M NA OAK ISLAND
N 15 73 83 MYRTLE BEACH
N 8 73 84 GEORGETOWN

10 p.m. Arthur

| 10:19 pm July 2, 2014

Arthur is on the precipice of being a hurricane and likely will become one early tomorrow.

The track has been shifted a little westward with some of the models carrying it over eastern North Carolina.

2014-07-02_22-13-46

The pressure continues to fall and is down to 988 mb.

Arthur Nearly A Hurricane, Pressure Dropping

| 4:03 pm July 2, 2014

As expected, Arthur is strengthening and is very close to being a hurricane. The pressure reported by Air Force Recon is 992 millibars, down from 995mb 2 hours ago. It will likely become a hurricane tonight.

7-2-2014 4-00-07 PM

A hurricane warning has been issued for the North Carolina coast from Surf City to Duck, including the Pamlico and Albemarle Sounds.

Forecast track shifted just a little west. The intensity forecast is not really changed. But the global models think that the storm will increase in intensity significantly and in size of wind field. The westward shift and the increase in the wind field prompted the upgrade to hurricane warnings.

The storm continues to try to become more organized. You can see new thunderstorms building on the east side of the storm.

arthur wed 4p ir

There are three reconnaissance planes in the storm right now sending back information on Arthur.

The New Potential Storm Surge Flooding Map

| 12:26 pm July 2, 2014

It is time to start learning about the new NWS Experimental Potential Storm Surge Flooding Map. The first ones were issued last evening by the National Hurricane Center for Arthur.

A few notes:

…The graphic shows a reasonable idea of worst-case scenario surge flooding from the storm. It is a map of the POTENTIAL flooding. It shows areas that COULD be affected by storm surge flooding, not necessarily how much water will be over each location in the shaded areas.

…There is a 10% exceedance factor, meaning that there is a 1 in 10 chance that the surge at any location could be higher.

…The flooding shows is only due to surge from the ocean, not rainfall flooding or flooding due to levee breaks or trapping.

…The product does take into account uncertainty in the track, size and intensity of the storm.

…Remember that weather conditions can change and so will this map.

…It is not a flood plain map. Storm surge can occur in areas that are NOT in a flood plain. Surge can occur miles inland.

…Evacuation zones may not correspond exactly with the surge flood map. People in evacuation aras should heed the advice of local emergency managers always.

…Remember that storm surge can occur well below and even after the center of the storm passes. In Ike on the Bolivar Peninsula, storm surge cut off evacuation routes nearly 36 hours before the arrival of the center.

…The product will be issued when hurricane or tropical storm watches are issued for any part of the Gulf or East Coasts of the United States.

Here is the current map from Advisory #7 at 10 a.m. this morning:

7-2-2014 12-13-08 PM

Zooming in on the Charleston SC area, a place that is very vulnerable to water inundation. The yellow shading indicates locations that could receive over 3 feet of flooding above ground, but less than 6 feet. The “above ground” indication is important since it takes into account land elevation. Keep in mind the 10% chance it could be

7-2-2014 11-21-43 AM

Take time to familiarize yourself with the product if you have interests along the Gulf of East Coast so that you will be ready to use it when a hurricane or tropical storm threatens.

Here is a short video on the product from the National Hurricane Center:

Melbourne Radar Loop

| 10:51 am July 2, 2014

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Notes on Arthur

| 10:22 am July 2, 2014

I will keep some notes going today on here about Arthur, updating them at the top of the post until the next advisory comes out.

AT 10 AM CDT
———————————————–
LOCATION…29.1N 79.1W
ABOUT 105 MI…165 KM ENE OF CAPE CANAVERAL FLORIDA
ABOUT 260 MI…420 KM SSE OF CHARLESTON SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS…60 MPH…95 KM/H
PRESENT MOVEMENT…N OR 360 DEGREES AT 7 MPH…11 KM/H
MINIMUM CENTRAL PRESSURE…997 MB…29.44 INCHES

Click image to enlarge

Click image to enlarge

As you can see from the updated graphic, tropical storm warnings have now been issued for the entire North Carolina coast.

There is still a tropical storm watch for a portion of the South Carolina coast.

There is a hurricane watch for the Outer Banks.

There are numerous tropical storm warnings in effect for the coastal waters offshore.

The official forecast track has been nudged slightly east but brings the center within 50 miles of Cape Hatteras during the pre-dawn hours Friday.

The wind probabilities are about the same as late last night, except they have increased slightly on the Outer Banks for tropical storm force winds, around 75-80%.

SATELLITE
The storm ingested a little dry air last night and took a hit in appearance, but it appears to be moistening again this morning. Tropical cyclones are like little steam engines, puffing up and down as thunderstorms develop and mature. Arthur is starting to look stronger on satellite.

arthur wed 10a ir

INTENSITY
Arthur is forecast to become a hurricane tomorrow and should peak at around 85 mph in intensity before it starts to weaken and lose tropical characteristics as it races northeast ahead of the approaching trough, moving over colder water.

RECON
No planes in the storm right now, but there are two low level missions that will reconnoiter the storm all day and night starting around noon. There are also three NOAA flights scheduled, including a high altitude flight for this evening.

Arthur He Does As He Pleases

| 10:08 pm July 1, 2014

The references to the Christopher Cross song from the movie Arthur are irresistible as we track our first tropical storm of the Atlantic season. Someone said today that it will only affect areas between the moon and New York City. Gotta love that one. My contribution is the title of this post.

First, let us reiterate that Arthur will have no direct impact on our weather in Alabama or the weather along the northern Gulf Coast. It will have a small, indirect hand in making the weather better through the Fourth of July weekend.

But, Arthur is a potential worst case scenario for forecasters and emergency managers. We have a relatively weak storm that has the potential to grow in to a significant hurricane pretty quickly while only a short distance from a coastline crowded with holiday vacationers.

Arthur will be strengthening more tomorrow while tracking more northeastward about 100 miles off the coast of northeastern Florida. It should become a hurricane tomorrow or tomorrow night.

By Thursday morning, the center should be about 125 miles southeast of Charleston, South Carolina and by nightfall, it should be about 80 miles southeast of Myrtle Beach.

The center may pass right over the Outer Banks of North Carolina early Friday morning as a strong Cat 1 hurricane with top winds of 85 mph.

Here is the NWS National Digital Forecast Database representation of the storm at 1 a.m. Friday morning, depicted in the wind field.

2014-07-01_22-09-18

On the graphic, I have overlain the probabilities of tropical storm force winds (39 mph – blue), strong tropical storm force winds (58 mph – yellow) and hurricane force winds (74 mph – red) on the little colored number stacks. You can see about an even chance places like Charleston and Myrtle Beach will see tropical storm force winds and a better chance along the North Carolina coast.

Click image to enlarge

Click image to enlarge

The best chance for hurricane force winds will be along the Outer Banks, but based on the official forecast, the probability for hurricane force winds there is still only about 20%. Hurricane force winds will be most likely along much of the Outer Banks early Friday morning, with improving conditions later in the day on the Fourth.

I have overlain the wind swatch along the official track as well, shown in blue, gray and red for TS, strong TS and hurricane force.

There is a tropical storm watch (shown in yellow) along the East Coast of Florida.

The impact to the South Carolina coast will not be tremendous, with a nearly even chance of tropical storm force winds. With the onshore flow ahead of the center, ides will be high, and there will almost certainly be flooding Charleston where it floods with any good inshore wind.

It is important to note that the forecast track can have errors. In fact, the “cone of uncertainty” from the NHC could carry the center as far west of Charleston SC or take it 150 miles east of Cape Hatteras. The good news is that the strongest wind field will be on the east, or oceanic, side of the storm.

The storm will quickly lose tropical characteristics as it races northeast, reaching Nova Scotia Saturday afternoon and Newfoundland Sunday evening.

If you are traveling to South Carolina or eastern North Carolina over the holiday weekend, check the latest forecasts and emergency information.

First Tropical Storm of the 2014 Season

| 10:20 am July 1, 2014

The National Hurricane Center has upgraded Tropical Depression One to Tropical Storm Arthur. The complete text of the advisory is below.

Arthur is expected to move slowly northward along the East Coast of Florida for the next couple of days as seen in the track graphic and gradually gaining strength as it curves northeastward Thursday and Friday become a hurricane near the coast of North Carolina. Track guidance is looking good because of the strong similarity of the various models.

Arthur Track

Arthur is not expected to have any direct impact on Alabama. Sinking motion on the western side of the storm will help to keep convection suppressed for the latter half of the week. Strong northerly flow aloft will bring some drier and slightly cooler air to our area for the Fourth of July.

-Brian-

BULLETIN
TROPICAL STORM ARTHUR ADVISORY NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012014
1100 AM EDT TUE JUL 01 2014

...DEPRESSION BECOMES A TROPICAL STORM OFFSHORE OF THE CENTRAL
FLORIDA ATLANTIC COAST...


SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.6N 79.3W
ABOUT 95 MI...155 KM SE OF CAPE CANAVERAL FLORIDA
ABOUT 80 MI...130 KM NNW OF FREEPORT GRAND BAHAMA ISLAND
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* EAST COAST OF FLORIDA FROM FORT PIERCE TO FLAGLER BEACH

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE WITHIN 24 TO 36 HOURS.

INTERESTS ELSEWHERE ALONG THE SOUTHEAST COAST OF THE UNITED STATES
SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...
INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST
OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE OF THE
UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL
METEOROLOGICAL SERVICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 AM EDT...1500 UTC...THE CENTER OF TROPICAL STORM ARTHUR WAS
LOCATED NEAR LATITUDE 27.6 NORTH...LONGITUDE 79.3 WEST. ARTHUR IS
MOVING TOWARD THE NORTHWEST NEAR 2 MPH...4 KM/H...AND THIS GENERAL
MOTION SHOULD CONTINUE THROUGH TONIGHT...FOLLOWED BY A TURN TOWARD
THE NORTH ON WEDNESDAY. ON THE FORECAST TRACK...THE CENTER OF THE
TROPICAL CYCLONE IS EXPECTED TO REMAIN JUST OFFSHORE AND MOVE EAST
OF THE EAST-CENTRAL COAST OF FLORIDA DURING THE NEXT DAY OR SO.  THE
SYSTEM IS FORECAST TO PASS EAST OF NORTHEASTERN FLORIDA ON WEDNESDAY
AND WEDNESDAY NIGHT.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH HIGHER
GUSTS.  ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 48
HOURS.  DURING THE PAST FEW HOURS...SETTLEMENT POINT OBSERVATION
SITE ON GRAND BAHAMA ISLAND REPORTED SUSTAINED WINDS OF 38 MPH...61
KM/H...WITH GUSTS TO 44 MPH...70 KM/H.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB...29.74 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH
AREA BY LATE TODAY.

RAINFALL...ARTHUR IS EXPECTED TO PRODUCE TOTAL RAINFALL
ACCUMULATIONS OF 1 TO 3 INCHES...MAINLY ACROSS THE EASTERN FLORIDA
PENINSULA. ISOLATED MAXIMUM AMOUNTS OF 5 INCHES ARE POSSIBLE THROUGH
WEDNESDAY.  RAINFALL AMOUNTS OF 2 TO 4 INCHES WITH ISOLATED MAXIMUM
AMOUNTS OF 6 INCHES ARE POSSIBLE OVER THE NORTHWESTERN BAHAMAS
THROUGH WEDNESDAY.


NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...200 PM EDT.
NEXT COMPLETE ADVISORY...500 PM EDT.

$$
FORECASTER STEWART