ATL: BONNIE - Post-Tropical - Discussion

[Aric Dunn]

I'm guessing they won't upgrade at 5pm but maybe 11pm.



Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

The only way they would upgrade at 11 is with another recon or some definite evidence of a well defined circ. Even if a huge ball of convection developed they would likely wait till next recon.

[cycloneye]

URNT15 KNHC 271949
AF307 01AAA INVEST HDOB 33 20160527
194030 2844N 07351W 9771 00325 //// +220 //// 146030 031 021 000 01
194100 2846N 07349W 9770 00326 //// +220 //// 143030 030 022 001 01
194130 2847N 07348W 9772 00326 //// +220 //// 141030 031 021 000 01
194200 2848N 07347W 9770 00328 //// +220 //// 140030 031 020 000 01
194230 2849N 07345W 9770 00330 //// +220 //// 140029 031 020 000 01
194300 2851N 07344W 9770 00330 //// +220 //// 137030 031 019 000 01
194330 2852N 07343W 9769 00331 //// +220 //// 135029 030 019 000 01
194400 2853N 07341W 9772 00330 //// +220 //// 135029 029 020 000 05
194430 2854N 07340W 9770 00332 //// +220 //// 136029 029 019 000 01
194500 2855N 07339W 9770 00332 //// +219 //// 136028 029 019 001 01
194530 2857N 07337W 9773 00328 //// +218 //// 136029 030 019 000 01
194600 2858N 07336W 9771 00331 //// +219 //// 137029 030 019 000 01
194630 2859N 07334W 9770 00332 //// +217 //// 136030 030 018 000 01
194700 2900N 07333W 9771 00333 //// +217 //// 137031 031 018 000 01
194730 2902N 07332W 9772 00332 //// +219 //// 136031 032 018 000 01
194800 2903N 07330W 9771 00335 //// +220 //// 138032 032 017 000 01
194830 2904N 07329W 9770 00336 //// +220 //// 138032 033 017 000 01
194900 2905N 07328W 9772 00336 //// +220 //// 136032 032 015 000 01
194930 2906N 07326W 9770 00338 //// +220 //// 136032 032 015 000 01
195000 2908N 07325W 9782 00327 //// +220 //// 131029 031 015 000 01
$$

[cycloneye]

[cycloneye]

A bunch of low 30,s at last set.

[TheAustinMan]

Helpful informational slide on what it means to have a "well-defined center" and what reconnaissance missions are looking for when investigating areas of interest:



In other words, there's not really an operational definition for a well-defined center, but the rough requirements are for the elliptical "area of uncertainty" where the center of circulation is located to be less than 75 nautical miles along its longest width (major axis). In addition, the longest width (major axis) should be less than 2x longer than the shortest width (minor axis) of that ellipse of uncertainty.

[ozonepete]

I'm guessing they won't upgrade at 5pm but maybe 11pm..

The only way they would upgrade at 11 is with another recon or some definite evidence of a well defined circ. Even if a huge ball of convection developed they would likely wait till next recon.

They are in the same bind we saw a number of times last year. It's moving at a good clip and getting too close to landfall to wait much longer. That's probably why they said if advisories are not initiated this afternoon they will give another special outlook at 8PM. They need people in the southeast to keep paying attention. I would think they can issue an upgrade with advisories at 8 or 11PM tonight if they need to since landfall is less than 48 hours away and there certainly is a very high chance this will be a TS by landfall.

[TheAustinMan]

NHC Atlantic Ops ‏@NHC_Atlantic 8s8 seconds ago
NHC will initiate advisories on Tropical Depression Two at 5 pm EDT/2100 UTC. This will include a TS Warning for the South Carolina coast.

[tarheelprogrammer]

What a difference a few hours makes. Looking more organized and clouds are not being blown off by shear around the center. Probably will be a TS tonight or early tomorrow morning. It hasn't hit the Gulf Stream yet either.

[cycloneye]

URNT15 KNHC 272009
AF307 01AAA INVEST HDOB 35 20160527
200030 2843N 07346W 9767 00331 //// +220 //// 141024 025 021 000 01
200100 2842N 07348W 9773 00326 //// +220 //// 141023 024 019 000 01
200130 2841N 07349W 9772 00325 //// +220 //// 141023 024 019 000 01
200200 2839N 07351W 9770 00326 //// +216 //// 142023 023 018 001 01
200230 2838N 07352W 9773 00322 //// +218 //// 146023 024 019 000 01
200300 2837N 07354W 9771 00324 //// +217 //// 146024 024 019 000 01
200330 2836N 07356W 9769 00325 //// +219 //// 143023 024 019 000 01
200400 2835N 07357W 9771 00322 //// +216 //// 145023 023 019 000 01
200430 2834N 07359W 9772 00321 //// +218 //// 146022 023 019 000 01
200500 2833N 07400W 9769 00322 //// +215 //// 142022 023 018 000 01
200530 2832N 07402W 9770 00321 //// +215 //// 144023 024 019 000 01
200600 2831N 07404W 9768 00322 //// +215 //// 143023 024 020 000 01
200630 2830N 07405W 9770 00319 //// +215 //// 143023 024 019 000 01
200700 2829N 07407W 9770 00315 //// +216 //// 147023 024 020 000 01
200730 2827N 07409W 9768 00311 //// +215 //// 148023 024 019 000 01
200800 2826N 07410W 9771 00303 //// +215 //// 150023 023 019 000 01
200830 2825N 07412W 9774 00299 //// +215 //// 153024 024 020 000 01
200900 2824N 07413W 9770 00299 //// +215 //// 153021 024 019 000 05
200930 2823N 07415W 9770 00300 //// +214 //// 154017 019 015 000 05
201000 2822N 07417W 9765 00302 //// +214 //// 156016 017 014 000 01
$$
;

[Yellow Evan]

No doubt in my mind this is a TC, and may have been one for several hours actually.

[cycloneye]

[cycloneye]

URNT15 KNHC 272019
AF307 01AAA INVEST HDOB 36 20160527
201030 2821N 07418W 9773 00296 //// +217 //// 157016 018 014 000 01
201100 2821N 07420W 9767 00300 //// +218 //// 162014 015 014 000 01
201130 2820N 07422W 9774 00293 //// +219 //// 163013 014 012 000 01
201200 2819N 07424W 9767 00299 //// +220 //// 155013 013 013 000 05
201230 2819N 07426W 9769 00297 //// +221 //// 158012 012 010 000 01
201300 2818N 07428W 9772 00293 //// +220 //// 156012 013 008 000 01
201330 2817N 07430W 9774 00291 //// +222 //// 157009 012 009 000 01
201400 2816N 07431W 9769 00294 //// +222 //// 154008 008 009 000 05
201430 2816N 07433W 9772 00293 //// +217 //// 162006 007 009 000 01
201500 2815N 07435W 9768 00296 //// +214 //// 183005 005 010 000 05
201530 2815N 07437W 9769 00294 //// +217 //// 197004 005 006 000 01
201600 2815N 07439W 9773 00292 //// +217 //// 196004 004 010 001 05
201630 2815N 07441W 9769 00296 //// +215 //// 194002 004 008 000 01
201700 2815N 07443W 9773 00292 //// +215 //// 294001 002 008 000 05
201730 2816N 07445W 9711 00336 //// +211 //// 044002 003 006 000 01
201800 2817N 07446W 9397 00614 //// +208 //// 043004 005 008 000 05
201830 2819N 07447W 8936 01047 //// +193 //// 039007 008 /// /// 05
201900 2821N 07448W 8543 01438 //// +171 //// 059006 007 011 000 05
201930 2822N 07449W 8217 01776 //// +153 //// 123006 007 009 001 05
202000 2824N 07450W 7880 02123 //// +130 //// 126006 007 010 000 01
$$

[cycloneye]

[SeGaBob]

NHC's intensity forecast might be interesting.

[cycloneye]

Plane leaves the area.Next mission will be early in the morning (8:30z) of Saturday May 28.

[GlennOBX]

NHC will initiate advisories on Tropical Depression Two at 5 pm EDT/2100 UTC. This will include a TS Warning for the South Carolina coast. - from NHC Atlantic Ops, on Twitter.

[cycloneye]

40 kts as peak.

[cycloneye]

BULLETIN
TROPICAL DEPRESSION TWO ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022016
500 PM EDT FRI MAY 27 2016

...SECOND TROPICAL CYCLONE OF THE SEASON FORMS OFF OF THE
SOUTHEASTERN UNITED STATES...
...TROPICAL STORM WARNING ISSUED FOR COASTAL SOUTH CAROLINA...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...28.5N 74.7W
ABOUT 435 MI...695 KM SE OF CHARLESTON SOUTH CAROLINA
ABOUT 440 MI...705 KM SE OF HILTON HEAD ISLAND SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES


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

A Tropical Storm Warning has been issued for the coast of South
Carolina from the Savannah River northeastward to Little River
Inlet.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Savannah River to Little River Inlet South Carolina

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

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 Tropical Depression Two was
located near latitude 28.5 North, longitude 74.7 West. The
depression is moving toward the west-northwest near 13 mph (20 km/h)
and this general motion is expected to continue for the next 24
hours. A reduction of the forward speed is expected by Saturday
night as the system nears the coast.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours, and the
depression is expected to become a tropical storm later tonight or
on Saturday.

The estimated minimum central pressure is 1009 mb (29.80 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are expected to first reach
the coast within the warning area by Saturday night, making outside
preparations difficult.

RAINFALL: The depression is expected to produce total rainfall
accumulations of 2 to 4 inches from the upper coast of Georgia
through eastern South Carolina and into southeastern North Carolina.

STORM SURGE: Storm surge inundation of 1 to 2 feet above ground
level is expected within the tropical storm warning area.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM EDT.
Next complete advisory at 1100 PM EDT.

$$
Forecaster Stewart

[TheAustinMan]

Remember the know what the cone means.

[Yellow Evan]

Code: Select all

                    * ATLANTIC     SHIPS INTENSITY FORECAST          *
                    * IR SAT DATA AVAILABLE,       OHC AVAILABLE     *
                    *  INVEST      AL912016  05/27/16  18 UTC        *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    30    31    32    34    37    40    41    43    41    41    41    40    40
V (KT) LAND       30    31    32    34    37    40    41    35    31    28    30    30    30
V (KT) LGEM       30    30    30    31    32    34    35    31    29    28    31    36    40
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP

SHEAR (KT)        19    20    15    13    19    21    21    22    23    25    17    20    16
SHEAR ADJ (KT)    -2    -1    -4    -1    -2    -4     0   -10    -3    -6    -1    -5    -1
SHEAR DIR        203   208   206   187   173   179   162   190   182   212   196   223   219
SST (C)         25.3  25.0  25.4  26.0  25.9  24.2  23.2  23.0  22.9  23.0  23.5  23.8  23.5
POT. INT. (KT)   107   105   108   114   113    97    90    88    87    88    91    93    92
ADJ. POT. INT.    95    92    95   100    98    84    77    75    75    75    77    79    78
200 MB T (C)   -57.0 -56.7 -56.6 -56.7 -56.6 -56.7 -56.8 -57.0 -56.8 -56.9 -56.9 -56.7 -56.7
200 MB VXT (C)  -1.1  -1.0  -0.5  -0.4  -0.4  -0.6  -0.3  -0.3   0.1   0.1   0.1   0.1   0.5
TH_E DEV (C)       5     6     6     5     6     4     6     5     8     5     7     5     6
700-500 MB RH     57    53    50    53    55    61    60    52    45    43    50    48    48
MODEL VTX (KT)     9     8     8     9     9     9     9     9     6     6     5     5     3
850 MB ENV VOR     2   -21   -38   -34   -19   -23   -14   -18    12   -39   -16   -24   -22
200 MB DIV         3    15   -16    19    53    17    23    34     5     1    18    -5     7
700-850 TADV       9     6     3     9     9     3     1     0     0     0     1     2     0
LAND (KM)        596   528   456   384   301   119    38   -14   -52   -42     6     7    17
LAT (DEG N)     28.2 xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x
LONG(DEG W)     74.2 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT)    10    10    10    11     9     6     3     2     2     3     3     3     4
HEAT CONTENT       0     0     0     0     0     1     0     0     0     0     0     0     0

  FORECAST TRACK FROM OFPI      INITIAL HEADING/SPEED (DEG/KT):300/ 10      CX,CY:  -8/  5
  T-12 MAX WIND:  30            PRESSURE OF STEERING LEVEL (MB):  692  (MEAN=618)
  GOES IR BRIGHTNESS TEMP. STD DEV.  50-200 KM RAD:  23.3 (MEAN=14.5)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  39.0 (MEAN=65.0)
  PRELIM RI PROB (DV .GE. 30 KT IN 24 HR):            1.0

                        INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
                         6   12   18   24   36   48   60   72   84   96  108  120
                        ----------------------------------------------------------
  SAMPLE MEAN CHANGE     1.   2.   3.   4.   6.   8.   9.  11.  11.  12.  13.  13.
  SST POTENTIAL          0.  -1.  -1.  -1.   0.   1.   3.   4.   5.   6.   6.   7.
  VERTICAL SHEAR MAG     1.   3.   4.   5.   6.   5.   1.  -2.  -7. -10. -13. -15.
  VERTICAL SHEAR ADJ     0.   1.   1.   1.   2.   3.   5.   6.   6.   7.   7.   7.
  VERTICAL SHEAR DIR     0.   0.   0.   1.   1.   1.   2.   3.   4.   5.   6.   7.
  PERSISTENCE            0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.   0.   0.   0.   0.
  200/250 MB TEMP.       0.   1.   1.   1.   3.   4.   5.   6.   7.   9.  10.  11.
  THETA_E EXCESS         0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -2.  -2.  -2.  -2.
  700-500 MB RH          0.   0.   0.   0.   0.   0.  -1.   0.   0.   0.   0.   0.
  MODEL VTX TENDENCY     0.  -1.  -1.  -1.  -2.  -3.  -4.  -8.  -9. -11. -12. -14.
  850 MB ENV VORTICITY   0.   0.  -1.  -1.  -1.  -2.  -2.  -2.  -3.  -3.  -4.  -4.
  200 MB DIVERGENCE      0.   0.  -1.   0.   0.   0.   0.   0.   0.   0.   0.   1.
  850-700 T ADVEC        0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  ZONAL STORM MOTION     0.   0.   0.   0.   1.   1.   1.   1.   1.   1.   1.   1.
  STEERING LEVEL PRES    0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.
  DAYS FROM CLIM. PEAK   0.   0.   0.   0.   0.   0.   0.   1.   1.   1.   1.   1.
  GOES PREDICTORS       -1.  -1.  -1.  -2.  -2.  -3.  -3.  -3.  -2.  -2.  -1.  -1.
  OCEAN HEAT CONTENT     0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.
                        ----------------------------------------------------------
  TOTAL CHANGE           1.   2.   4.   7.  10.  12.  13.  11.  11.  11.  10.  10.

                CURRENT MAX WIND (KT):   30. LAT, LON:   28.2    74.2

      ** 2015 ATLANTIC RI INDEX AL912016 INVEST     05/27/16  18 UTC **
 (SHIPS-RII PREDICTOR TABLE for 30 KT OR MORE MAXIMUM WIND INCREASE IN NEXT 24-h)
 
     Predictor             Value   RI Predictor Range  Scaled Value(0-1) % Contribution
 12 HR PERSISTENCE (KT):     0.0     -49.5  to   33.0       0.60           2.9
 850-200 MB SHEAR (KT) :    17.2      28.8  to    2.9       0.45           1.0
 HEAT CONTENT (KJ/cm2) :     0.0       0.0  to  155.1       0.00           0.0
 STD DEV OF IR BR TEMP :    23.3      37.5  to    2.9       0.41           0.9
 2nd PC OF IR BR TEMP  :     0.1       2.8  to   -3.1       0.46           1.0
 MAXIMUM WIND (kt)     :    30.0      22.5  to  121.0       0.21           0.2
 D200 (10**7s-1)       :    14.8     -23.1  to  181.5       0.19           0.2
 POT = MPI-VMAX (KT)   :    66.0      28.4  to  139.1       0.34           0.4
 % AREA WITH TPW <45 mm:    26.6     100.0  to    0.0       0.73           0.4
 BL DRY-AIR FLUX (w/m2):   164.0     960.3  to  -67.1       0.78           0.0
 
 SHIPS Prob RI for 20kt/ 12hr RI threshold=   3% is   0.6 times sample mean ( 5.5%)
 SHIPS Prob RI for 25kt/ 24hr RI threshold=  10% is   0.9 times sample mean (11.6%)
 SHIPS Prob RI for 30kt/ 24hr RI threshold=   7% is   1.0 times sample mean ( 7.2%)
 SHIPS Prob RI for 35kt/ 24hr RI threshold=   0% is   0.0 times sample mean ( 4.2%)
 SHIPS Prob RI for 40kt/ 24hr RI threshold=   0% is   0.0 times sample mean ( 2.8%)
 SHIPS Prob RI for 45kt/ 36hr RI threshold=   0% is   0.0 times sample mean ( 4.9%)
 SHIPS Prob RI for 55kt/ 48hr RI threshold=   0% is   0.0 times sample mean ( 5.1%)
 
 Matrix of RI probabilities
 ---------------------------------------------------------------------
  RI (kt / h)  | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48
 ---------------------------------------------------------------------
   SHIPS-RII:     3.3%   10.0%    6.9%    0.0%    0.0%    0.0%    0.0%
    Logistic:     1.9%    7.7%    3.5%    1.2%    0.0%    1.5%    0.4%
    Bayesian:     0.1%    0.1%    0.0%    0.0%    0.0%    0.0%    0.0%
   Consensus:     1.8%    5.9%    3.5%    0.4%    0.0%    0.5%    0.1%

   ##         ANNULAR HURRICANE INDEX (AHI) AL912016 INVEST     05/27/16  18 UTC         ##
   ## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3                          ##
   ## AHI=  0   (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL912016 INVEST     05/27/2016  18 UTC **
TIME(HR)   0-12  12-24(0-24)  24-36(0-36)  36-48(0-48)
CLIMO(%)     0      0(  0)       0(  0)       0(  0)     <-- PROB BASED ON INTENSITY ONLY
PROB(%)      0      0(  0)       0(  0)       0(  0)     <-- FULL MODEL PROB (RAN NORMALLY)

** DSHIPS INTENSITY FORECAST ADJUSTED RELATIVE TO ONSET OF ERC WEAKENING PHASE **
      TIME (HR)      0     6    12    18    24    36    48    60    72    84    96   108   120
>24HR AGO (DSHIPS)  30    31    32    34    37    40    41    35    31    28    30    30    30
 18HR AGO           30    29    30    32    35    38    39    33    29    26    28    28    28
 12HR AGO           30    27    26    28    31    34    35    29    25    22    24    24    24
  6HR AGO           30    24    21    20    23    26    27    21    17   DIS   DIS   DIS   DIS
      NOW                              CURRENT INTENSITY < 83 KT
  IN  6HR                              INTENSITY IN  6HR < 83 KT
  IN 12HR                              INTENSITY IN 12HR < 83 KT