Atlantic/2015/02L/Archive/2

## Public Advisory

TROPICAL STORM BILL ADVISORY NUMBER 2

WIKI-HURRICANES FORECAST CENTER

400 PM CDT MON JUN 15 2015

...BILL MAY BECOME A HURRICANE BEFORE LANDFALL...

SUMMARY OF 400 PM CDT...1600 UTC...INFORMATION

LOCATION...26.3N 93.4W

ABOUT 270 MI...435 KM SSE OF GALVESTON TEXAS

MAXIMUM SUSTAINED WINDS...45 KT...50 MPH...85 KM/H

MINIMUM BAROMETRIC PRESSURE... 1006 MB...29.72 INCHES

PRESENT MOVEMENT...WNW OR 275 DEGREES AT 5 KT...6 MPH...9 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 4:00 am CDT, the center of Tropical Storm Bill was located at 26.3N, 93.4W, or about 250 miles (435 km) southwest of Galveston, Texas. Maximum sustained winds were 45 knots (50 mph, 85 km/h), with higher gusts. The minimum barometric pressure was 1007 millibars (inHg; 29.74 inHg), and the system was moving west-northwest at 5 knots (6 mph, 9 km/h). Environmental conditions are expected to be generally favorable for steady intensification, and there is a slight chance Bill becomes a hurricane before the cyclone moves ashore the Texas coastline on Tuesday.

NEXT ADVISORY

Next complete advisory at 10:00 pm CDT.

$$

Forecaster YE

## Discussion

TROPICAL STORM BILL SPECIAL DISCUSSION NUMBER 1

WIKI-HURRICANES FORECAST CENTER

11:00 AM CDT MON JUN 15 2015

Since the issuance of the previous advisory, Bill has become better organized with impressive outflow, a rarity for this basin, and a very well-defined center. However, due to sheer lack of evidence, with no TAF-basedB Dvorak fixes, CMISS ADT, or airplane reconnaissance, we can not adjust the initial intensity upward, though I think they'll find a stronger system when the Hurricane Hunters hunt this down tonight. If anything, the initial intensity warrants being lowered based on a T1.0/25 knts from SSD and SAB. However, I find these estimates are extremely unreasonable and borderline outrageous, and the wrong pattern is likely be used. Thus, the above estimates are not being factored in. Therefore, the intensity has been held at 45 knts.

The environment that Bill is currently located is rapidly becoming conducive for strengthening. Assuming that the upcoming Air Force reconnaissance plane shows Bill a stronger system, there remains a brief window of opportunity for Bill to intensity into a minimal hurricane. However, Bill is not expected to have much time to strengthen before making landfall along the Texas coast, as Bill will likely have only about 12 to 24 hours before striking land. The new forecast is higher than the previous one, and accounts for the fact that rapid intensification is possible prior to landfall, like many Texas systems. What is bizarre is that several models have indicated unusual intensity maintenance or even deepening of Bill over North Texas or Oklahoma. While I am not ready to show this, the rate of weakening is slower than the previous package.

A general consensus between models exists, and the current and previous WHFC forecast track uses the forecast consensus shifted northward to account for Bill's location further north than the last model initialization. Bill is expected to travel generally northwestward before curving northward through landfall.

A hurricane watch or possibly even a hurricane warning will likely be required for a portion of the upper Texas coast at any time.

INIT 15/2100Z 26.3N 93.4W 45KT 50MPH

12HR 16/0600Z 27.4N 94.5W 55KT 65MPH

24HR 16/1800Z 28.9N 95.7W 65KT 75MPH ... ONSHORE

36HR 17/0600Z 30.8N 96.1W 405T 50MPH ... INLAND

48HR 17/1800Z 32.7N 95.7W 35KT 40MPH ... INLAND

72HR 18/0600Z 35.8N 93.5W 30KT 30MPH ... INLAND

96 hr Dissipated
$$

Forecasters YE