Slide 1

Michael L. Jurewicz, Sr. WFO Binghamton, NY Northeast Regional Operational Workshop November 5, 2009

Slide 2

AR TC Tracks and PRE Locations All AR TC TracksAll AR PPTC Tracks; with PRE centroids (colored dots)

Slide 3

Mid-level Streamlines Representative TC Tracks TC Rainfall PREs LL e -Ridge Axis See inset UL Jet Conceptual Model: LOT PREs Ahead Of SR Or AR TCs Revised and updated from Fig. 13 of Bosart and Carr (1978)

Slide 4

Bill

Slide 5

Brief History of Bill Himself Bill was initially a Cape Verde tropical wave, which became a named storm on 15 August From 19-23 August, Bill attained hurricane status well off the U.S. East Coast (briefly reached Category 3) From 23-25 August, Bill transitioned to an extra- tropical system, as it recurved into the westerlies southeast of the Canadian maritime provinces

Slide 6

Bills Approximate Path

Slide 7

Heavy Rainfall Event across New England

Slide 8

Afternoon Rainfall on 22 August Up to 7 (175 mm) rainfall

Slide 9

Radar Loop

Slide 10

Water Vapor Loop

Slide 11

250 mb at 12z, 22 August

Slide 12

250 mb at 00z, 23 August

Slide 13

200 mb Height/Wind/PV, 14z, 22 August

Slide 14

200 mb Height/Wind/PV, 22z, 22 August Height Rises / PV Destruction

Slide 15

Surface Analysis, 18z, 22 August Possible PRE

Slide 16

850 mb Moisture Transport Possible PRE

Slide 17

700 mb Heights, 925 mb Winds/Theta-E, at 21z, 22 August Near intersection of Bills moisture and pre-existing moist plume

Slide 18

Parcel Trajectories into Central New England Bills Track

Slide 19

Bill Summary Bill fit into the AR track for potential PRE-producing systems One main heavy rain episode took place on the periphery of Bills influence Southern NH on 22 August 4-7 (up to 175 mm) of rain fell within just a few hours, causing flash flooding Transient nature of heavier rain bands precluded excessive rainfall/runoff problems elsewhere

Slide 20

Danny

Slide 21

Brief History of Danny Himself Danny was initially a Cape Verde tropical wave, and took several days to become a named storm Finally, on 26 August, it attained Tropical Storm status east of the Bahamas From 26-29 August, Danny remained a Tropical Storm well off the Southeast U.S. coast From 29-31 August, Danny weakened to a Tropical Depression, and ultimately transitioned to an extra- tropical system, as it recurved off the U.S. East Coast

Slide 22

Dannys Approximate Path

Slide 23

Heavy Rainfall Event across the Mid-Atlantic Region

Slide 24

Late Night/Early Morning Rainfall, 27-28 August 4-8 (100- 200 mm) rainfall

Slide 25

Radar Loop

Slide 26

250 mb at 00z, 28 August

Slide 27

Water Vapor Loop

Slide 28

700 mb Heights, 925 mb Winds/Theta-E, at 05z, 28 August Axis of tro pical moisture Separate moist axis

Slide 29

850 mb at 00z, 28 August

Slide 30

Parcel Trajectories into the Mid- Atlantic Region

Slide 31

200 mb Height/Jet/PV, 02z, 28 August

Slide 32

200 mb Height/Jet/PV, 09z, 28 August

Slide 33

SB CAPE Analysis, 06z, 28 August

Slide 34

Heavy Rainfall Event Just off the Mid-Atlantic Coast

Slide 35

Late Afternoon/Overnight Rainfall, 28-29 August Widespread 5-10 (up to 250 mm) rainfall

Slide 36

Radar Loop, 28-29 August

Slide 37

250 mb at 00z, 29 August

Slide 38

Water Vapor, 28-29 August

Slide 39

700 mb Heights, 925 mb Winds/Theta-E, at 03z, 29 August Tropical Moisture Axis

Slide 40

SB CAPE Analysis, 00z, 29 August Possible PRE

Slide 41

Surface Analysis, 00z, 29 August Possible PRE

Slide 42

850 mb Analysis, 00z on 29 August

Slide 43

Parcel Trajectories into the Mid- Atlantic Coastal Region Dannys Track

Slide 44

Danny Summary Danny fit into the AR track for potential PRE-producing systems Two distinct heavy rain episodes took place on the periphery of Dannys influence Event that most resembled a PRE took place just offshore, 28- 29 August Heavy rain/flash flooding that occurred in the Baltimore area appeared to lack sufficient moisture contributions from Danny or jet interactions Lack of a direct moisture connection with the TC, as well as a relatively cool stable air mass, seemed to protect much of the Northeastern U.S. from excessive rainfall