ALL forecasts from this Forecast Center are based on my analysis and knowledge of various forecast tools, including information contained in NHC products. These forecasts are my product based on this, and are not copies from any other entity.
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Good evening everyone!
Tropical Storm Arthur…the first Tropical Storm of the season has improved in structure greatly since my early morning forecast.
The following information was available on Arthur as of the Intermediate Advisory issued at 8:00 p.m. EDT from the NHC in Miami:
8:00 PM EDT Tue Jul 1
Location: 27.8°N 79.3°W
Min pressure: 1003 mb / 29.62 in
Max sustained: 50 mph
TROPICAL CYCLONE POTENTIAL IMPACT GRAPHIC (THIS IS INTERACTIVE…YOU MAY CLICK ON A DIFFERENT AREA TO CHANGE IT)
There has been no change in strength of Arthur since 5:00 p.m. The storm is currently stationary, as steering currents are very weak at the moment, based on analysis of the current steering layers map from CIMSS.
CURRENT STEERING LAYERS MAP
The current run of the forecast steering layers maps suggest that Arthur should begin more of a NNW to N motion by late tomorrow or very early on Thursday. Based on analysis of the forecast steering layers maps, and current water vapor loop imagery, I pretty much agree with the NHC forecast track at the moment. However, the steering layers forecast maps valid for 00Z this evening, indicate the center of Arthur COULD pass closer to the west, and possibly allowing for him to skirt the SC/NC coast, up to the OBX area. Any deviation to the left, would almost place the OBX in the direct path. Based on the uncertainty of exactly when the approaching trof may begin to affect Arthur, and the steering layers forecast pretty much showing the same track, I prefer the NHC/TVCN/TVCC track, however I am slightly to the left of these, but to the right of the NGX.
Information in the NHC Public Advisory indicates Tropical Storm Warnings and Hurricane Watch may be required for portions north of Arthur late tonight. Based on the stationary motion of Arthur, I believe they may hold off until a definite northward motion begins. Regardless, residents along the Eastern Seaboard coast from GA to the NC OBX should monitor this system closely for issuance of any watches and warnings for their areas.
NHC PUBLIC ADVISORY
NHC FORECAST DISCUSSION
NWS LOCAL HURRICANE STATEMENTS
Arthur has become a little better organized over the past few hours, with what appears to be a CDO beginning to develop, as seen in satellite loop imagery. However, Arthur is currently tilted to the SE due to NWLY shear, as an upper level anticyclone is just north of him. The center of circulation is just very slightly to the west of the heaviest convection, based on IR2 Shortwave loop images. My current forecast thinking has not changed much, and I pretty much concur with the NHC intensity forecast. Albeit, the wind shear forecast does indicate shear to abate in about 12-18 hours, which then allows for an upper level anticyclone to become established over the center of Arthur. Zonal shear forecast indicates at that time, the center of Arthur should remain along the ZERO zonal shear line.
Based on this, analysis of SST and maps, and current forecast track, I concur with the NHC that Arthur should attain Category 1 Hurricane status. However, IF the shear forecast does pan out, and if the storm can fight off drier air, I am not expecting Rapid Intensification, however there could be a steadier strengthening prior to the storm encountering cooler SST’s and shear. Given this, I cannot fully rule out the probability of Arthur attaining minimal Category 2 status for a brief time. Another note on the wind shear forecast…should it behave as forecast, I would expect Arthur to attain 65 -70 mph Tropical Storm Status sometime lat tomorrow, save any dry air intrusion.
As it stands right now, most of the major impact should remain offshore, unless the track moves further left. In any event, possible heavy rain, and gusty winds may be experienced along the coastal areas further North. As the storm approaches from the South, onshore winds will drive water ashore, and into inland waterways closer to the coast along the SC/NC areas. Minor coastal flooding and beach erosion is likely at he time of high tide.
If a Hurricane Watch is issued for your area, you should begin preparations immediately. Residents along the SEUS coast should monitor NOAA Weather Radio, and NWS Local Statements and Advisories.
I will have another update in the a.m., most likely after the intermediate advisory.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS
OFFICIAL SKYWARN SPOTTER (ADVANCED)