Tropical Storm Chris Discussion Number 7

Wiki-Hurricanes Forecast Center

5:00 PM EDT Mon Jul 9 2018

Chris has looked a fair bit ragged this morning due to a combination of an influx of dry continental air pooled in the wake of the passing cold front and cooler upwelled waters due to Chris' quasi-stationary motion over the past few days. Dew points in North and South Carolina are around 13C and some of this is making its way into the tropical storm, while a nearby buoy in the southern part of Chris' circulation has been recording locally falling sea surface temperatures to 26C. Numerous decaying convection and outflow boundaries in the southeastern quadrant are indicative of these tepid conditions. Satellite images show a newly developed central area of overcast wrapping around a banding eye, but microwave data from 1457Z show that Chris still has much work to do to rebuild its inner core, with only a partial central band with a large pool of internal subsidence. Nonetheless, convection is expanding and it is fairly clear that the system has resumed intensification. Air Force reconnaissance aicraft running a mission around Chris this afternoon found a decently sized swath of 50kt surface winds and strong flight-level winds, with a peak of 73kt in the southwestern quadrant. Weakest winds are in the northeastern quadrant, at around an estimated 40kt. Using the typical conversion factors from Uhlhorn et. al (2006), the intensity for Chris this advisory has been raised to 60 kt.

Satellite images show Chris is stationary this afternoon, and recon is confirming the still wnadering center of circulation. An upper-level anticyclone is allowing for development of the core of the system without interference by unfavorable winds. Chris is expected to exit its holding pattern tonight as a shortwave trough now over Ontario approaches the system. An accelerated northeasterly heading is expected to commence tomorrow with the trough closer to the system. Tropical Storm Chris sacrificed its larger core this morning to tighten a smaller one in the midst of dry air, but in order to strengthen more appreciably Chris needs to start moving away from its nursery grounds. Environmental sea surface temperatures are near 28C, though they have been depressed two or so degrees. Conditions are rather dry, but with some baroclinic support and warm waters from the periphery of the Gulf Stream, convection is expected to continue and allow for some intensification before cooler northerly waters and extratropically suited conditions return past the Gulf Stream, weakening the system. Towards the end of the


INIT 09/2100Z 60 KT 70 MPH

12H 10/0600Z 65 KT 75 MPH

24H 10/1800Z 80 KT 90 MPH

36H 11/0600Z 90 KT 100 MPH

48H 11/1800Z 90 KT 100 MPH

72H 12/1800Z 65 KT 75 MPH

96H 13/1800Z 45 KT 50 MPH...EXTRATROPICAL


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